diff --git a/Lib/unittest/case.py b/Lib/unittest/case.py
--- a/Lib/unittest/case.py
+++ b/Lib/unittest/case.py
@@ -634,7 +634,10 @@ class TestCase(object):
 
     def _baseAssertEqual(self, first, second, msg=None):
         """The default assertEqual implementation, not type specific."""
-        if not first == second:
+        with warnings.catch_warnings():
+            warnings.simplefilter("ignore", BytesWarning)
+            not_equal = (not first == second)
+        if not_equal:
             standardMsg = '%s != %s' % (safe_repr(first), safe_repr(second))
             msg = self._formatMessage(msg, standardMsg)
             raise self.failureException(msg)
@@ -767,7 +770,10 @@ class TestCase(object):
                         seq_type_name)
 
         if differing is None:
-            if seq1 == seq2:
+            with warnings.catch_warnings():
+                warnings.simplefilter("ignore", BytesWarning)
+                equal = (seq1 == seq2)
+            if equal:
                 return
 
             seq1_repr = safe_repr(seq1)
@@ -794,9 +800,12 @@ class TestCase(object):
                                  (i, seq_type_name))
                     break
 
-                if item1 != item2:
+                with warnings.catch_warnings():
+                    warnings.simplefilter("ignore", BytesWarning)
+                    not_equal = (item1 != item2)
+                if not_equal:
                     differing += ('\nFirst differing element %d:\n%s\n%s\n' %
-                                 (i, item1, item2))
+                                 (i, safe_repr(item1), safe_repr(item2)))
                     break
             else:
                 if (len1 == len2 and seq_type is None and
@@ -809,7 +818,7 @@ class TestCase(object):
                              'elements.\n' % (seq_type_name, len1 - len2))
                 try:
                     differing += ('First extra element %d:\n%s\n' %
-                                  (len2, seq1[len2]))
+                                  (len2, safe_repr(seq1[len2])))
                 except (TypeError, IndexError, NotImplementedError):
                     differing += ('Unable to index element %d '
                                   'of first %s\n' % (len2, seq_type_name))
@@ -818,7 +827,7 @@ class TestCase(object):
                              'elements.\n' % (seq_type_name, len2 - len1))
                 try:
                     differing += ('First extra element %d:\n%s\n' %
-                                  (len1, seq2[len1]))
+                                  (len1, safe_repr(seq2[len1])))
                 except (TypeError, IndexError, NotImplementedError):
                     differing += ('Unable to index element %d '
                                   'of second %s\n' % (len1, seq_type_name))
diff --git a/Lib/unittest/test/test_case.py b/Lib/unittest/test/test_case.py
--- a/Lib/unittest/test/test_case.py
+++ b/Lib/unittest/test/test_case.py
@@ -595,6 +595,23 @@ class Test_TestCase(unittest.TestCase, T
         self.assertTupleEqual((), ())
         self.assertSequenceEqual([], ())
 
+        a = ['str']
+        b = [b'bytes']
+        with warnings.catch_warnings():
+            warnings.simplefilter("error", BytesWarning)
+            self.assertRaises(unittest.TestCase.failureException,
+                              self.assertEqual, 'str', b'bytes')
+            self.assertRaises(unittest.TestCase.failureException,
+                              self.assertListEqual, a, b)
+            self.assertRaises(unittest.TestCase.failureException,
+                              self.assertListEqual, tuple(a), tuple(b))
+            self.assertRaises(unittest.TestCase.failureException,
+                              self.assertSequenceEqual, a, tuple(b))
+            self.assertRaises(unittest.TestCase.failureException,
+                              self.assertSequenceEqual, b+b, b)
+            self.assertRaises(unittest.TestCase.failureException,
+                              self.assertSequenceEqual, b, b+b)
+
         a = [0, 'a', []]
         b = []
         self.assertRaises(unittest.TestCase.failureException,