diff --git a/_pytest/assertion/__init__.py b/_pytest/assertion/__init__.py
index edda06345..cf9265330 100644
--- a/_pytest/assertion/__init__.py
+++ b/_pytest/assertion/__init__.py
@@ -25,9 +25,6 @@ def pytest_addoption(parser):
                             expression information.""")
 
 
-def pytest_namespace():
-    return {'register_assert_rewrite': register_assert_rewrite}
-
 
 def register_assert_rewrite(*names):
     """Register one or more module names to be rewritten on import.
diff --git a/pytest.py b/pytest.py
index e376e417e..26667f5e5 100644
--- a/pytest.py
+++ b/pytest.py
@@ -9,6 +9,7 @@ __all__ = [
     'hookspec',
     'hookimpl',
     '__version__',
+    'register_assert_rewrite'
 ]
 
 if __name__ == '__main__': # if run as a script or by 'python -m pytest'
@@ -22,6 +23,7 @@ from _pytest.config import (
     main, UsageError, _preloadplugins, cmdline,
     hookspec, hookimpl
 )
+from _pytest.assertion import register_assert_rewrite
 from _pytest import __version__
 
 _preloadplugins() # to populate pytest.* namespace so help(pytest) works