diff --git a/HACKING.rst b/HACKING.rst
index c2346e3c244..bd1e069c366 100644
--- a/HACKING.rst
+++ b/HACKING.rst
@@ -19,7 +19,6 @@ Below you can find a list of checks specific to this repository.
 - [N329] Use assertCountEqual() instead of assertItemsEqual()
 - [N330] Use assertEqual(*empty*, observed) instead of
          assertEqual(observed, *empty*)
-- [N331] Detect wrong usage with assertTrue(isinstance()).
 - [N332] Use assertEqual(expected_http_code, observed_http_code) instead of
          assertEqual(observed_http_code, expected_http_code).
 - [N340] Check usage of <module>.i18n (and neutron.i18n)
diff --git a/neutron/hacking/checks.py b/neutron/hacking/checks.py
index 66dd8addf0b..a066b8e7988 100644
--- a/neutron/hacking/checks.py
+++ b/neutron/hacking/checks.py
@@ -119,17 +119,6 @@ def check_assertempty(logical_line, filename):
             yield (0, msg)
 
 
-@core.flake8ext
-def check_assertisinstance(logical_line, filename):
-    """N331 - Enforce using assertIsInstance."""
-    if 'neutron/tests/' in filename:
-        if re.search(r"assertTrue\(\s*isinstance\(\s*[^,]*,\s*[^,]*\)\)",
-                     logical_line):
-            msg = ("N331: Use assertIsInstance(observed, type) instead "
-                   "of assertTrue(isinstance(observed, type))")
-            yield (0, msg)
-
-
 @core.flake8ext
 def check_assertequal_for_httpcode(logical_line, filename):
     """N332 - Enforce correct ordering for httpcode in assertEqual."""
diff --git a/neutron/tests/unit/hacking/test_checks.py b/neutron/tests/unit/hacking/test_checks.py
index efe0741d971..cec4489b1e9 100644
--- a/neutron/tests/unit/hacking/test_checks.py
+++ b/neutron/tests/unit/hacking/test_checks.py
@@ -162,29 +162,6 @@ class HackingTestCase(base.BaseTestCase):
                         pass_code2 % ec,
                         "neutron/tests/test_assert.py"))))
 
-    def test_assertisinstance(self):
-        fail_code = """
-               self.assertTrue(isinstance(observed, ANY_TYPE))
-               """
-        pass_code1 = """
-               self.assertEqual(ANY_TYPE, type(observed))
-               """
-        pass_code2 = """
-               self.assertIsInstance(observed, ANY_TYPE)
-               """
-        self.assertEqual(
-            1, len(list(
-                checks.check_assertisinstance(
-                    fail_code, "neutron/tests/test_assert.py"))))
-        self.assertEqual(
-            0, len(list(
-                checks.check_assertisinstance(
-                    pass_code1, "neutron/tests/test_assert.py"))))
-        self.assertEqual(
-            0, len(list(
-                checks.check_assertisinstance(
-                    pass_code2, "neutron/tests/test_assert.py"))))
-
     def test_assertequal_for_httpcode(self):
         fail_code = """
                 self.assertEqual(res.status_int, webob.exc.HTTPNoContent.code)
diff --git a/tox.ini b/tox.ini
index 4f6df4f5764..443097ff662 100644
--- a/tox.ini
+++ b/tox.ini
@@ -250,7 +250,6 @@ extension =
   N328 = neutron.hacking.checks:check_asserttruefalse
   N329 = neutron.hacking.checks:check_assertitemsequal
   N330 = neutron.hacking.checks:check_assertempty
-  N331 = neutron.hacking.checks:check_assertisinstance
   N332 = neutron.hacking.checks:check_assertequal_for_httpcode
   N340 = neutron.hacking.checks:check_oslo_i18n_wrapper
   N341 = neutron.hacking.checks:check_builtins_gettext