diff --git a/Include/dictobject.h b/Include/dictobject.h
index 44b0838..ec2e0c8 100644
--- a/Include/dictobject.h
+++ b/Include/dictobject.h
@@ -90,7 +90,8 @@
 
 PyAPI_DATA(PyTypeObject) PyDict_Type;
 
-#define PyDict_Check(op) PyObject_TypeCheck(op, &PyDict_Type)
+#define PyDict_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_DICT_SUBCLASS)
 #define PyDict_CheckExact(op) ((op)->ob_type == &PyDict_Type)
 
 PyAPI_FUNC(PyObject *) PyDict_New(void);
diff --git a/Include/intobject.h b/Include/intobject.h
index 1f4846e..51d3e1b 100644
--- a/Include/intobject.h
+++ b/Include/intobject.h
@@ -27,7 +27,8 @@
 
 PyAPI_DATA(PyTypeObject) PyInt_Type;
 
-#define PyInt_Check(op) PyObject_TypeCheck(op, &PyInt_Type)
+#define PyInt_Check(op) \
+		 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_INT_SUBCLASS)
 #define PyInt_CheckExact(op) ((op)->ob_type == &PyInt_Type)
 
 PyAPI_FUNC(PyObject *) PyInt_FromString(char*, char**, int);
diff --git a/Include/listobject.h b/Include/listobject.h
index d9012ce..db3124e 100644
--- a/Include/listobject.h
+++ b/Include/listobject.h
@@ -40,7 +40,8 @@
 
 PyAPI_DATA(PyTypeObject) PyList_Type;
 
-#define PyList_Check(op) PyObject_TypeCheck(op, &PyList_Type)
+#define PyList_Check(op) \
+		PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_LIST_SUBCLASS)
 #define PyList_CheckExact(op) ((op)->ob_type == &PyList_Type)
 
 PyAPI_FUNC(PyObject *) PyList_New(Py_ssize_t size);
diff --git a/Include/longobject.h b/Include/longobject.h
index eef4e9b..3893ad6 100644
--- a/Include/longobject.h
+++ b/Include/longobject.h
@@ -11,7 +11,8 @@
 
 PyAPI_DATA(PyTypeObject) PyLong_Type;
 
-#define PyLong_Check(op) PyObject_TypeCheck(op, &PyLong_Type)
+#define PyLong_Check(op) \
+		PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_LONG_SUBCLASS)
 #define PyLong_CheckExact(op) ((op)->ob_type == &PyLong_Type)
 
 PyAPI_FUNC(PyObject *) PyLong_FromLong(long);
diff --git a/Include/object.h b/Include/object.h
index b0817e6..0f6ff77 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -376,7 +376,8 @@
 PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */
 PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */
 
-#define PyType_Check(op) PyObject_TypeCheck(op, &PyType_Type)
+#define PyType_Check(op) \
+	PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_TYPE_SUBCLASS)
 #define PyType_CheckExact(op) ((op)->ob_type == &PyType_Type)
 
 PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);
@@ -517,6 +518,17 @@
 /* Objects support nb_index in PyNumberMethods */
 #define Py_TPFLAGS_HAVE_INDEX (1L<<17)
 
+/* These flags are used to determine if a type is a subclass. */
+#define Py_TPFLAGS_INT_SUBCLASS		(1L<<23)
+#define Py_TPFLAGS_LONG_SUBCLASS	(1L<<24)
+#define Py_TPFLAGS_LIST_SUBCLASS	(1L<<25)
+#define Py_TPFLAGS_TUPLE_SUBCLASS	(1L<<26)
+#define Py_TPFLAGS_STRING_SUBCLASS	(1L<<27)
+#define Py_TPFLAGS_UNICODE_SUBCLASS	(1L<<28)
+#define Py_TPFLAGS_DICT_SUBCLASS	(1L<<29)
+#define Py_TPFLAGS_BASE_EXC_SUBCLASS	(1L<<30)
+#define Py_TPFLAGS_TYPE_SUBCLASS	(1L<<31)
+
 #define Py_TPFLAGS_DEFAULT  ( \
                              Py_TPFLAGS_HAVE_GETCHARBUFFER | \
                              Py_TPFLAGS_HAVE_SEQUENCE_IN | \
@@ -530,6 +542,7 @@
                             0)
 
 #define PyType_HasFeature(t,f)  (((t)->tp_flags & (f)) != 0)
+#define PyType_FastSubclass(t,f)  PyType_HasFeature(t,f)
 
 
 /*
diff --git a/Include/pyerrors.h b/Include/pyerrors.h
index 9532e32..9671692 100644
--- a/Include/pyerrors.h
+++ b/Include/pyerrors.h
@@ -95,14 +95,12 @@
 /* */
 
 #define PyExceptionClass_Check(x)					\
-	(PyClass_Check((x))						\
-	 || (PyType_Check((x)) && PyType_IsSubtype(			\
-		     (PyTypeObject*)(x), (PyTypeObject*)PyExc_BaseException)))
-
+	(PyClass_Check((x)) || (PyType_Check((x)) &&			\
+	  PyType_FastSubclass((PyTypeObject*)(x), Py_TPFLAGS_BASE_EXC_SUBCLASS)))
 
 #define PyExceptionInstance_Check(x)			\
 	(PyInstance_Check((x)) ||			\
-	 (PyType_IsSubtype((x)->ob_type, (PyTypeObject*)PyExc_BaseException)))
+	 PyType_FastSubclass((x)->ob_type, Py_TPFLAGS_BASE_EXC_SUBCLASS))
 
 #define PyExceptionClass_Name(x)				   \
 	(PyClass_Check((x))					   \
diff --git a/Include/stringobject.h b/Include/stringobject.h
index 5f8a6f0..03c3777 100644
--- a/Include/stringobject.h
+++ b/Include/stringobject.h
@@ -55,7 +55,8 @@
 PyAPI_DATA(PyTypeObject) PyBaseString_Type;
 PyAPI_DATA(PyTypeObject) PyString_Type;
 
-#define PyString_Check(op) PyObject_TypeCheck(op, &PyString_Type)
+#define PyString_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_STRING_SUBCLASS)
 #define PyString_CheckExact(op) ((op)->ob_type == &PyString_Type)
 
 PyAPI_FUNC(PyObject *) PyString_FromStringAndSize(const char *, Py_ssize_t);
diff --git a/Include/tupleobject.h b/Include/tupleobject.h
index 8c37cab..738cea1 100644
--- a/Include/tupleobject.h
+++ b/Include/tupleobject.h
@@ -33,7 +33,8 @@
 
 PyAPI_DATA(PyTypeObject) PyTuple_Type;
 
-#define PyTuple_Check(op) PyObject_TypeCheck(op, &PyTuple_Type)
+#define PyTuple_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_TUPLE_SUBCLASS)
 #define PyTuple_CheckExact(op) ((op)->ob_type == &PyTuple_Type)
 
 PyAPI_FUNC(PyObject *) PyTuple_New(Py_ssize_t size);
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 33aa185..0bad8c3 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -392,7 +392,8 @@
 
 PyAPI_DATA(PyTypeObject) PyUnicode_Type;
 
-#define PyUnicode_Check(op) PyObject_TypeCheck(op, &PyUnicode_Type)
+#define PyUnicode_Check(op) \
+                 PyType_FastSubclass((op)->ob_type, Py_TPFLAGS_UNICODE_SUBCLASS)
 #define PyUnicode_CheckExact(op) ((op)->ob_type == &PyUnicode_Type)
 
 /* Fast access macros */
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 1cb3ee6..587dad3 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2112,7 +2112,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_DICT_SUBCLASS,	/* tp_flags */
 	dictionary_doc,				/* tp_doc */
 	dict_traverse,				/* tp_traverse */
 	dict_tp_clear,				/* tp_clear */
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 0cd819c..c6ea6a4 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -300,7 +300,8 @@
     PyObject_GenericGetAttr,    /*tp_getattro*/
     PyObject_GenericSetAttr,    /*tp_setattro*/
     0,                          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,  /*tp_flags*/
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC |
+    	Py_TPFLAGS_BASE_EXC_SUBCLASS,  /*tp_flags*/
     PyDoc_STR("Common base class for all exceptions"), /* tp_doc */
     (traverseproc)BaseException_traverse, /* tp_traverse */
     (inquiry)BaseException_clear, /* tp_clear */
diff --git a/Objects/intobject.c b/Objects/intobject.c
index f504af7..9ffc295 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -1138,7 +1138,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_INT_SUBCLASS,	/* tp_flags */
 	int_doc,				/* tp_doc */
 	0,					/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/listobject.c b/Objects/listobject.c
index 3083b5f..2ac5e86 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2672,7 +2672,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_LIST_SUBCLASS,	/* tp_flags */
  	list_doc,				/* tp_doc */
  	(traverseproc)list_traverse,		/* tp_traverse */
  	(inquiry)list_clear,			/* tp_clear */
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 4d886cd..ef3e242 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -3418,7 +3418,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_LONG_SUBCLASS,	/* tp_flags */
 	long_doc,				/* tp_doc */
 	0,					/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 416457d..ca94d72 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -4017,7 +4017,7 @@
 	0,					/* tp_setattro */
 	&string_as_buffer,			/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_STRING_SUBCLASS,		/* tp_flags */
 	string_doc,				/* tp_doc */
 	0,					/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index c85b35a..dacc3ee 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -669,7 +669,7 @@
 	0,					/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TUPLE_SUBCLASS, /* tp_flags */
 	tuple_doc,				/* tp_doc */
  	(traverseproc)tupletraverse,		/* tp_traverse */
 	0,					/* tp_clear */
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 20b530c..4b0816e 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2288,7 +2288,7 @@
 	(setattrofunc)type_setattro,		/* tp_setattro */
 	0,					/* tp_as_buffer */
 	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,		/* tp_flags */
+		Py_TPFLAGS_BASETYPE | Py_TPFLAGS_TYPE_SUBCLASS,	/* tp_flags */
 	type_doc,				/* tp_doc */
 	(traverseproc)type_traverse,		/* tp_traverse */
 	(inquiry)type_clear,			/* tp_clear */
@@ -2967,6 +2967,26 @@
 	if (type->tp_flags & base->tp_flags & Py_TPFLAGS_HAVE_CLASS) {
 		COPYVAL(tp_dictoffset);
 	}
+
+	/* Setup fast subclass flags */
+	if (PyType_IsSubtype(base, (PyTypeObject*)PyExc_BaseException))
+		type->tp_flags |= Py_TPFLAGS_BASE_EXC_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyType_Type))
+		type->tp_flags |= Py_TPFLAGS_TYPE_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyInt_Type))
+		type->tp_flags |= Py_TPFLAGS_INT_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyLong_Type))
+		type->tp_flags |= Py_TPFLAGS_LONG_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyString_Type))
+		type->tp_flags |= Py_TPFLAGS_STRING_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyUnicode_Type))
+		type->tp_flags |= Py_TPFLAGS_UNICODE_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyTuple_Type))
+		type->tp_flags |= Py_TPFLAGS_TUPLE_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyList_Type))
+		type->tp_flags |= Py_TPFLAGS_LIST_SUBCLASS;
+	else if (PyType_IsSubtype(base, &PyDict_Type))
+		type->tp_flags |= Py_TPFLAGS_DICT_SUBCLASS;
 }
 
 static void
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 290e8df..a49fe39 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -7967,7 +7967,7 @@
     0,			 		/* tp_setattro */
     &unicode_as_buffer,			/* tp_as_buffer */
     Py_TPFLAGS_DEFAULT | Py_TPFLAGS_CHECKTYPES |
-	    Py_TPFLAGS_BASETYPE,	/* tp_flags */
+	    Py_TPFLAGS_BASETYPE | Py_TPFLAGS_UNICODE_SUBCLASS,	/* tp_flags */
     unicode_doc,			/* tp_doc */
     0,					/* tp_traverse */
     0,					/* tp_clear */