diff --git a/_pytest/assertion/util.py b/_pytest/assertion/util.py
index 258fee8a8..13a31a4a9 100644
--- a/_pytest/assertion/util.py
+++ b/_pytest/assertion/util.py
@@ -162,12 +162,18 @@ def assertrepr_compare(config, op, left, right):
 
 
 def _diff_text(left, right, verbose=False):
-    """Return the explanation for the diff between text
+    """Return the explanation for the diff between text or bytes
 
     Unless --verbose is used this will skip leading and trailing
     characters which are identical to keep the diff minimal.
+
+    If the input are bytes they will be safely converted to text.
     """
     explanation = []
+    if isinstance(left, py.builtin.bytes):
+        left = u(repr(left)[1:-1]).replace(r'\n', '\n')
+    if isinstance(right, py.builtin.bytes):
+        right = u(repr(right)[1:-1]).replace(r'\n', '\n')
     if not verbose:
         i = 0  # just in case left or right has zero length
         for i in range(min(len(left), len(right))):
diff --git a/testing/test_assertion.py b/testing/test_assertion.py
index fbe44eb73..abd745415 100644
--- a/testing/test_assertion.py
+++ b/testing/test_assertion.py
@@ -185,6 +185,19 @@ class TestAssert_reprcompare:
         assert expl[1] == py.builtin._totext('- £€', 'utf-8')
         assert expl[2] == py.builtin._totext('+ £', 'utf-8')
 
+    def test_mojibake(self):
+        # issue 429
+        left = 'e'
+        right = '\xc3\xa9'
+        if not isinstance(left, py.builtin.bytes):
+            left = py.builtin.bytes(left, 'utf-8')
+            right = py.builtin.bytes(right, 'utf-8')
+        expl = callequal(left, right)
+        for line in expl:
+            assert isinstance(line, py.builtin.text)
+        msg = py.builtin._totext('\n').join(expl)
+        assert msg
+
 
 def test_python25_compile_issue257(testdir):
     testdir.makepyfile("""