diff --git a/tensorflow/contrib/autograph/__init__.py b/tensorflow/contrib/autograph/__init__.py
index 361cf2d77c7..4f8ef2d8a15 100644
--- a/tensorflow/contrib/autograph/__init__.py
+++ b/tensorflow/contrib/autograph/__init__.py
@@ -29,6 +29,10 @@ from tensorflow.contrib.autograph.impl.api import converted_call
 from tensorflow.contrib.autograph.impl.api import do_not_convert
 from tensorflow.contrib.autograph.impl.api import RunMode
 from tensorflow.contrib.autograph.impl.api import to_code
+from tensorflow.contrib.autograph.core.errors import improved_errors
+from tensorflow.contrib.autograph.core.errors import rewrite_graph_construction_error
+from tensorflow.contrib.autograph.core.errors import GraphConstructionError
+from tensorflow.contrib.autograph.core.errors import TfRuntimeError
 from tensorflow.contrib.autograph.impl.api import to_graph
 from tensorflow.contrib.autograph.lang.directives import set_element_type
 from tensorflow.contrib.autograph.lang.directives import set_loop_options
@@ -42,10 +46,12 @@ _allowed_symbols = [
     'convert',
     'converted_call',
     'do_not_convert',
+    'improved_errors',
     'to_code',
     'to_graph',
     # Overloaded operators
     'operators',
+    'rewrite_graph_construction_error',
     # Python language "extensions"
     'set_element_type',
     'set_loop_options',
diff --git a/tensorflow/contrib/autograph/core/BUILD b/tensorflow/contrib/autograph/core/BUILD
index 833f9dced81..1873045a921 100644
--- a/tensorflow/contrib/autograph/core/BUILD
+++ b/tensorflow/contrib/autograph/core/BUILD
@@ -19,6 +19,7 @@ py_library(
     srcs = [
         "config.py",
         "converter.py",
+        "errors.py",
         "naming.py",
     ],
     srcs_version = "PY2AND3",
@@ -30,6 +31,31 @@ py_library(
     ],
 )
 
+py_test(
+    name = "errors_test",
+    srcs = ["errors_test.py"],
+    srcs_version = "PY2AND3",
+    deps = [
+        ":core",
+        "//tensorflow/python:array_ops",
+        "//tensorflow/python:client_testlib",
+        "//tensorflow/python:control_flow_ops",
+        "//tensorflow/python:dtypes",
+        "//tensorflow/python:math_ops",
+        "//tensorflow/python:random_ops",
+    ],
+)
+
+py_test(
+    name = "naming_test",
+    srcs = ["naming_test.py"],
+    srcs_version = "PY2AND3",
+    deps = [
+        ":core",
+        "//tensorflow/python:client_testlib",
+    ],
+)
+
 py_library(
     name = "test_lib",
     srcs = [
@@ -47,13 +73,3 @@ py_library(
         "@six_archive//:six",
     ],
 )
-
-py_test(
-    name = "naming_test",
-    srcs = ["naming_test.py"],
-    srcs_version = "PY2AND3",
-    deps = [
-        ":core",
-        "//tensorflow/python:client_testlib",
-    ],
-)
diff --git a/tensorflow/contrib/autograph/core/errors.py b/tensorflow/contrib/autograph/core/errors.py
new file mode 100644
index 00000000000..e58745337a3
--- /dev/null
+++ b/tensorflow/contrib/autograph/core/errors.py
@@ -0,0 +1,272 @@
+# Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Error rewriting logic.
+
+Contains the functions responsible for rewriting tracebacks of errors raised
+in AutoGraph (AG) code to refer to user written code, so that errors only refer
+to the original user code.
+
+When 'user code' is used in comments it refers to the original source code that
+the user wrote and is converting using AutoGraph.
+"""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+import contextlib
+import logging
+import sys
+import traceback
+
+from tensorflow.contrib.autograph.pyct.origin_info import CodeLocation
+from tensorflow.python.framework import errors_impl
+from tensorflow.python.util import tf_inspect
+
+
+class GraphConstructionError(Exception):
+  """Error for graph construction errors from AutoGraph generated code."""
+
+  def __init__(self, original_error, custom_traceback):
+    self.original_error = original_error
+    self.custom_traceback = custom_traceback
+    super(GraphConstructionError, self).__init__()
+
+  def __str__(self):
+    traceback_str = ''.join(traceback.format_list(self.custom_traceback))
+    return ('Traceback (most recent call last):\n' + traceback_str + '\n' + str(
+        self.original_error) + '\n')
+
+
+class TfRuntimeError(Exception):
+  """Error wrapper for runtime errors raised by AutoGraph generated code."""
+
+  def __init__(self, op_name, op_message, custom_traceback):
+    self.op_name = op_name
+    self.op_message = op_message
+    self.custom_traceback = custom_traceback
+    super(TfRuntimeError, self).__init__()
+
+  def __str__(self):
+    message = '%s\n\nCaused by op %r, defined at:\n' % (self.op_message,
+                                                        self.op_name)
+    return message + ''.join(traceback.format_list(self.custom_traceback))
+
+
+def _rewrite_frame(source_map, cleaned_traceback, stack_frame_indices):
+  """Rewrites the stack frames at the given indices using the given source map.
+
+  Args:
+    source_map: Dict[CodeLocation, OriginInfo], a mapping between the user and
+        AG generated code.
+    cleaned_traceback: List[Tuple[text, text, text, text]], the current
+        traceback.
+    stack_frame_indices: Iterable[Int], frame indices to possibly rewrite if
+        there are matching source mapping keys.
+
+  Returns:
+    None
+  """
+  for frame_index in stack_frame_indices:
+    # (file_path, line number, function name, code)
+    file_path, line_number, _, _ = cleaned_traceback[frame_index]
+    source_map_key = CodeLocation(file_path=file_path, line_number=line_number)
+    found_mapping = source_map_key in source_map
+    if found_mapping:
+      cleaned_traceback[frame_index] = source_map[source_map_key].as_frame()
+
+
+# TODO(znado): Make more robust to name changes in the rewriting logic.
+def _remove_rewrite_frames(tb):
+  """Remove stack frames containing the error rewriting logic."""
+  cleaned_tb = []
+  for f in tb:
+    if 'ag__.rewrite_graph_construction_error' not in f[3]:
+      cleaned_tb.append(f)
+  return cleaned_tb
+
+
+def rewrite_graph_construction_error(source_map):
+  """Rewrites errors raised by non-AG APIs inside AG generated code.
+
+  Meant to be called from the try/except block inside each AutoGraph generated
+  function.  Only rewrites the traceback frames corresponding to the function
+  that this is called from.  When we raise a GraphConstructionError at the end
+  it is then caught by calling functions, where they can be responsible for
+  rewriting their own frames.
+
+  Args:
+    source_map: Dict[CodeLocation, OriginInfo], a mapping between the user and
+        AG generated code.
+
+  Raises:
+    GraphConstructionError: The rewritten underlying error.
+    Exception: The underlying error, if it could not be rewritten.
+  """
+  error_info = sys.exc_info()
+  _, original_error, e_traceback = error_info
+  assert original_error is not None
+  try:
+    _, _, _, func_name, _, _ = tf_inspect.stack()[1]
+    # The latest function call is added to the beginning of a traceback, but
+    # when rewriting the traceback of multiple function calls the previous
+    # functions' except blocks may have already rewritten their own frames so
+    # we want to copy over all of the previous frames. We may have rewritten
+    # previous frames only if the error is a GraphConstructionError.
+    if isinstance(original_error, GraphConstructionError):
+      cleaned_traceback = traceback.extract_tb(e_traceback)
+      previous_traceback = original_error.custom_traceback
+      cleaned_traceback = [cleaned_traceback[0]] + previous_traceback
+    else:
+      cleaned_traceback = traceback.extract_tb(e_traceback)
+    cleaned_traceback = _remove_rewrite_frames(cleaned_traceback)
+
+    current_frame_indices = []
+    # This code is meant to be called from the try/except block that wraps a
+    # function body.  Here we look for all frames that came from the function
+    # that this wraps, look for any matching line numbers in the source
+    # mapping, and then rewrite them if matches are found.
+    for fi, frame in enumerate(cleaned_traceback):
+      _, _, frame_func_name, _ = frame
+      if frame_func_name == func_name:
+        current_frame_indices.append(fi)
+        break
+    if current_frame_indices:
+      _rewrite_frame(source_map, cleaned_traceback, current_frame_indices)
+
+    if isinstance(original_error, GraphConstructionError):
+      original_error.custom_traceback = cleaned_traceback
+      new_error = original_error
+    else:
+      new_error = GraphConstructionError(original_error, cleaned_traceback)
+  except Exception:
+    logging.exception('Error while rewriting AutoGraph error:')
+    raise original_error
+  else:
+    raise new_error
+  finally:
+    # Addresses warning https://docs.python.org/2/library/sys.html#sys.exc_info.
+    del e_traceback
+
+
+def rewrite_tf_runtime_error(error, source_map):
+  """Rewrites TensorFlow runtime errors raised by ops created in AG code.
+
+  Args:
+    error: error_impl.OpError, an TensorFlow error that will have its traceback
+        rewritten.
+    source_map: Dict[CodeLocation, OriginInfo], a mapping between the user and
+        AG generated code.
+
+  Returns:
+    A TfRuntimeError with a traceback rewritten according to the given
+    source mapping.
+  """
+  # Check for cases where we leave a user method and re-enter it in the
+  # traceback.  This is done by looking at the function names when the
+  # filenames are from any files the user code is in.  If we find a case where
+  # we return to a user method after leaving it then we cut out the frames in
+  # between because we assume this means these in between frames are from
+  # internal AutoGraph code that shouldn't be included.
+  #
+  # An example of this is:
+  #
+  #  File "file1.py", line 57, in my_func
+  #    ...
+  #  File "control_flow_ops.py", line 231, in cond
+  #    ...
+  #  File "control_flow_ops.py", line 1039, in inner_cond
+  #    ...
+  #  File "file1.py", line 68, in my_func
+  #    ...
+  #
+  # Where we would remove the control_flow_ops.py frames because we re-enter
+  # my_func in file1.py.
+  #
+  # The source map keys are (file_path, line_number) so get the set of all user
+  # file_paths.
+  try:
+    all_user_files = set(k.file_path for k in source_map)
+    cleaned_traceback = []
+    last_user_frame_index = None
+    last_user_user_file_path = None
+    last_user_user_fn_name = None
+    for fi, frame in enumerate(error.op.traceback):
+      frame_file_path, frame_line_number, _, _ = frame
+      src_map_key = CodeLocation(
+          file_path=frame_file_path, line_number=frame_line_number)
+      if frame_file_path in all_user_files:
+        if src_map_key in source_map:
+          original_fn_name = source_map[src_map_key].function_name
+          if (last_user_frame_index is not None and
+              last_user_user_file_path == frame_file_path):
+            if last_user_user_fn_name == original_fn_name:
+              cleaned_traceback = cleaned_traceback[:last_user_frame_index]
+            else:
+              cleaned_traceback = cleaned_traceback[:last_user_frame_index + 1]
+          last_user_user_fn_name = original_fn_name
+        else:
+          last_user_user_fn_name = None
+        last_user_frame_index = fi
+        last_user_user_file_path = frame_file_path
+      cleaned_traceback.append(frame)
+
+    for fi in range(len(cleaned_traceback)):
+      _rewrite_frame(source_map, cleaned_traceback, [fi])
+    op_name = error.op.name
+    op_message = error.message
+    rewritten_error = TfRuntimeError(op_name, op_message, cleaned_traceback)
+    return rewritten_error
+  except Exception:  # pylint: disable=broad-except
+    logging.exception('Error while rewriting AutoGraph error:')
+    return error
+
+
+# TODO(znado): Add arg to enable different levels of error rewriting.
+@contextlib.contextmanager
+def improved_errors(converted_function):
+  """Context manager that rewrites runtime errors.
+
+  This context manager will rewrite runtime errors so that their traceback
+  is relative to the original code before conversion.
+
+  Use with the output of to_graph, and wrap the execution of respective ops.
+  Example:
+
+    converted_my_func = ag.to_graph(my_func)
+    ops = converted_my_func(...)
+
+    with ag.improved_errors(converted_my_func):
+      sess.run(ops)
+
+  Args:
+    converted_function: Callable[..., Any], the output of a to_graph call
+
+  Yields:
+    None
+
+  Raises:
+    TfRuntimeError: if any OpError originates in the converted code, it will
+        be wrapped into a TfRuntimeError
+    ValueError: If converted_function is not generated by AutoGraph
+  """
+  if (getattr(converted_function, 'ag_source_map', None) is None or
+      not converted_function.ag_source_map):
+    raise ValueError(
+        'converted_function must be the result of an autograph.to_graph call')
+  try:
+    yield
+  except errors_impl.OpError as e:
+    raise rewrite_tf_runtime_error(e, converted_function.ag_source_map)
diff --git a/tensorflow/contrib/autograph/core/errors_test.py b/tensorflow/contrib/autograph/core/errors_test.py
new file mode 100644
index 00000000000..7be54563a1a
--- /dev/null
+++ b/tensorflow/contrib/autograph/core/errors_test.py
@@ -0,0 +1,116 @@
+# Copyright 2018 The TensorFlow Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+# ==============================================================================
+"""Tests for errors module."""
+
+from __future__ import absolute_import
+from __future__ import division
+from __future__ import print_function
+
+from tensorflow.contrib.autograph.core import errors
+from tensorflow.contrib.autograph.pyct import origin_info
+from tensorflow.python.framework import dtypes
+from tensorflow.python.framework import errors as tf_errors
+from tensorflow.python.ops import array_ops
+from tensorflow.python.platform import test
+from tensorflow.python.util import tf_inspect
+
+
+def zero_div():
+  return array_ops.constant(10, dtype=dtypes.int32) // 0
+
+
+def zero_div_caller():
+  a = zero_div() + 2
+  return a
+
+
+class RuntimeErrorsTest(test.TestCase):
+
+  def setUp(self):
+    self._fake_origin = origin_info.OriginInfo('new file', 'new func', 96, 0,
+                                               'print("hello world!")')
+
+  def test_error_replacement(self):
+    _, zero_div_lineno = tf_inspect.getsourcelines(zero_div)
+    src_map = {
+        errors.CodeLocation(
+            file_path=__file__, line_number=zero_div_lineno + 1):
+            self._fake_origin
+    }
+    with self.assertRaises(errors.TfRuntimeError) as cm:
+      z = zero_div_caller()
+      zero_div_caller.ag_source_map = src_map
+      with errors.improved_errors(zero_div_caller):
+        with self.test_session() as sess:
+          sess.run(z)
+    expected = cm.exception
+    current_traceback = expected.custom_traceback
+    for frame in current_traceback:
+      self.assertNotEqual('zero_div', frame[2])
+    self.assertTrue(
+        any(self._fake_origin.as_frame() == frame
+            for frame in current_traceback))
+
+  def test_error_not_found(self):
+    src_map = {
+        errors.CodeLocation(file_path=__file__, line_number=-1):
+            self._fake_origin
+    }
+    with self.assertRaises(errors.TfRuntimeError) as cm:
+      z = zero_div_caller()
+      zero_div_caller.ag_source_map = src_map
+      with errors.improved_errors(zero_div_caller):
+        with self.test_session() as sess:
+          sess.run(z)
+    expected = cm.exception
+    current_traceback = expected.custom_traceback
+    self.assertTrue(any('zero_div' in frame[2] for frame in current_traceback))
+    for frame in current_traceback:
+      self.assertNotEqual(frame, self._fake_origin.as_frame())
+
+  def test_rewriting_error(self):
+    _, zero_div_lineno = tf_inspect.getsourcelines(zero_div)
+    src_map = {
+        errors.CodeLocation(
+            file_path=__file__, line_number=zero_div_lineno + 1):
+            None
+    }
+    with self.assertRaisesRegexp(tf_errors.InvalidArgumentError,
+                                 'Integer division by zero'):
+      z = zero_div_caller()
+      zero_div_caller.ag_source_map = src_map
+      with errors.improved_errors(zero_div_caller):
+        with self.test_session() as sess:
+          sess.run(z)
+
+  def test_no_ag_source_map(self):
+    with self.assertRaisesRegexp(
+        ValueError,
+        'converted_function must be the result of an autograph.to_graph call'):
+      with errors.improved_errors(None):
+        pass
+
+  def test_bad_ag_source_map(self):
+    with self.assertRaisesRegexp(
+        ValueError,
+        'converted_function must be the result of an autograph.to_graph call'):
+      src_map = None
+      zero_div_caller.ag_source_map = src_map
+      with errors.improved_errors(None):
+        pass
+
+
+if __name__ == '__main__':
+  test.main()
diff --git a/tensorflow/contrib/autograph/pyct/origin_info.py b/tensorflow/contrib/autograph/pyct/origin_info.py
index 2b05836e467..b3c6a43d37f 100644
--- a/tensorflow/contrib/autograph/pyct/origin_info.py
+++ b/tensorflow/contrib/autograph/pyct/origin_info.py
@@ -20,6 +20,16 @@ from __future__ import print_function
 from collections import namedtuple
 
 
+class CodeLocation(namedtuple('CodeLocation', ('file_path', 'line_number'))):
+  """Location of a line of code.
+
+  Attributes:
+    file_path: text, the full path to the file containing the code.
+    line_number: Int, the 1-based line number of the code in its file.
+  """
+  pass
+
+
 class OriginInfo(
     namedtuple('OriginInfo', ('file_path', 'function_name', 'line_number',
                               'column_offset', 'source_code_line'))):
@@ -32,4 +42,11 @@ class OriginInfo(
     * original user code
   """
 
-  pass
+  def as_frame(self):
+    """Makes a traceback frame tuple.
+
+    Returns:
+      A tuple of (file_path, line_number, function_name, source_code_line).
+    """
+    return (self.file_path, self.line_number, self.function_name,
+            self.source_code_line)