diff -r 1c72e9c1b3b4 Lib/test/test_codeccallbacks.py
--- a/Lib/test/test_codeccallbacks.py	Sat May 02 09:47:28 2015 +0100
+++ b/Lib/test/test_codeccallbacks.py	Sat May 02 14:43:04 2015 +0300
@@ -1046,6 +1046,24 @@ class CodecCallbackTest(unittest.TestCas
                 with self.assertRaises(TypeError):
                     data.decode(encoding, "test.replacing")
 
+    def test_fake_error_class(self):
+        handlers = [
+            codecs.strict_errors,
+            codecs.ignore_errors,
+            codecs.replace_errors,
+            codecs.backslashreplace_errors,
+            codecs.namereplace_errors,
+            codecs.xmlcharrefreplace_errors,
+            codecs.lookup_error('surrogateescape'),
+            codecs.lookup_error('surrogatepass'),
+        ]
+        for cls in UnicodeEncodeError, UnicodeDecodeError, UnicodeTranslateError:
+            class FakeUnicodeError(str):
+                __class__ = cls
+            for handler in handlers:
+                with self.subTest(handler=handler, error_class=cls):
+                    self.assertRaises(TypeError, handler, FakeUnicodeError())
+
 
 if __name__ == "__main__":
     unittest.main()
diff -r 1c72e9c1b3b4 Python/codecs.c
--- a/Python/codecs.c	Sat May 02 09:47:28 2015 +0100
+++ b/Python/codecs.c	Sat May 02 14:43:04 2015 +0300
@@ -689,15 +689,16 @@ PyObject *PyCodec_StrictErrors(PyObject 
 PyObject *PyCodec_IgnoreErrors(PyObject *exc)
 {
     Py_ssize_t end;
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    PyObject *cls = (PyObject *)exc->ob_type;
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         if (PyUnicodeEncodeError_GetEnd(exc, &end))
             return NULL;
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeDecodeError)) {
         if (PyUnicodeDecodeError_GetEnd(exc, &end))
             return NULL;
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeTranslateError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeTranslateError)) {
         if (PyUnicodeTranslateError_GetEnd(exc, &end))
             return NULL;
     }
@@ -712,8 +713,9 @@ PyObject *PyCodec_IgnoreErrors(PyObject 
 PyObject *PyCodec_ReplaceErrors(PyObject *exc)
 {
     Py_ssize_t start, end, i, len;
+    PyObject *cls = (PyObject *)exc->ob_type;
 
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         PyObject *res;
         int kind;
         void *data;
@@ -732,14 +734,14 @@ PyObject *PyCodec_ReplaceErrors(PyObject
         assert(_PyUnicode_CheckConsistency(res, 1));
         return Py_BuildValue("(Nn)", res, end);
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeDecodeError)) {
         if (PyUnicodeDecodeError_GetEnd(exc, &end))
             return NULL;
         return Py_BuildValue("(Cn)",
                              (int)Py_UNICODE_REPLACEMENT_CHARACTER,
                              end);
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeTranslateError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeTranslateError)) {
         PyObject *res;
         int kind;
         void *data;
@@ -766,7 +768,8 @@ PyObject *PyCodec_ReplaceErrors(PyObject
 
 PyObject *PyCodec_XMLCharRefReplaceErrors(PyObject *exc)
 {
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    PyObject *cls = (PyObject *)exc->ob_type;
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         PyObject *restuple;
         PyObject *object;
         Py_ssize_t i;
@@ -872,8 +875,9 @@ PyObject *PyCodec_BackslashReplaceErrors
     unsigned char *outp;
     int ressize;
     Py_UCS4 c;
+    PyObject *cls = (PyObject *)exc->ob_type;
 
-    if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeDecodeError)) {
         unsigned char *p;
         if (PyUnicodeDecodeError_GetStart(exc, &start))
             return NULL;
@@ -903,7 +907,7 @@ PyObject *PyCodec_BackslashReplaceErrors
         Py_DECREF(object);
         return Py_BuildValue("(Nn)", res, end);
     }
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         if (PyUnicodeEncodeError_GetStart(exc, &start))
             return NULL;
         if (PyUnicodeEncodeError_GetEnd(exc, &end))
@@ -911,7 +915,7 @@ PyObject *PyCodec_BackslashReplaceErrors
         if (!(object = PyUnicodeEncodeError_GetObject(exc)))
             return NULL;
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeTranslateError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeTranslateError)) {
         if (PyUnicodeTranslateError_GetStart(exc, &start))
             return NULL;
         if (PyUnicodeTranslateError_GetEnd(exc, &end))
@@ -977,7 +981,8 @@ static int ucnhash_initialized = 0;
 
 PyObject *PyCodec_NameReplaceErrors(PyObject *exc)
 {
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    PyObject *cls = (PyObject *)exc->ob_type;
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         PyObject *restuple;
         PyObject *object;
         Py_ssize_t i;
@@ -1150,7 +1155,8 @@ PyCodec_SurrogatePassErrors(PyObject *ex
     Py_ssize_t start;
     Py_ssize_t end;
     PyObject *res;
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    PyObject *cls = (PyObject *)exc->ob_type;
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         unsigned char *outp;
         if (PyUnicodeEncodeError_GetStart(exc, &start))
             return NULL;
@@ -1227,7 +1233,7 @@ PyCodec_SurrogatePassErrors(PyObject *ex
         Py_DECREF(object);
         return restuple;
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeDecodeError)) {
         unsigned char *p;
         Py_UCS4 ch = 0;
         if (PyUnicodeDecodeError_GetStart(exc, &start))
@@ -1312,7 +1318,8 @@ PyCodec_SurrogateEscapeErrors(PyObject *
     Py_ssize_t start;
     Py_ssize_t end;
     PyObject *res;
-    if (PyObject_IsInstance(exc, PyExc_UnicodeEncodeError)) {
+    PyObject *cls = (PyObject *)exc->ob_type;
+    if (PyObject_IsSubclass(cls, PyExc_UnicodeEncodeError)) {
         char *outp;
         if (PyUnicodeEncodeError_GetStart(exc, &start))
             return NULL;
@@ -1343,7 +1350,7 @@ PyCodec_SurrogateEscapeErrors(PyObject *
         Py_DECREF(object);
         return restuple;
     }
-    else if (PyObject_IsInstance(exc, PyExc_UnicodeDecodeError)) {
+    else if (PyObject_IsSubclass(cls, PyExc_UnicodeDecodeError)) {
         PyObject *str;
         unsigned char *p;
         Py_UCS2 ch[4]; /* decode up to 4 bad bytes. */