diff --git a/Lib/UserList.py b/Lib/UserList.py
index d4a8d2f..1146060 100644
--- a/Lib/UserList.py
+++ b/Lib/UserList.py
@@ -51,9 +51,20 @@
             return self.__class__(other + self.data)
         else:
             return self.__class__(list(other) + self.data)
+    def __iadd__(self, other):
+        if isinstance(other, UserList):
+            self.data += other.data
+        elif isinstance(other, type(self.data)):
+            self.data += other
+        else:
+            self.data += list(other)
+        return self
     def __mul__(self, n):
         return self.__class__(self.data*n)
     __rmul__ = __mul__
+    def __imul__(self, n):
+        self.data *= n
+        return self
     def append(self, item): self.data.append(item)
     def insert(self, i, item): self.data.insert(i, item)
     def pop(self, i=-1): return self.data.pop(i)
diff --git a/Lib/UserString.py b/Lib/UserString.py
index 070b3e1..34f3216 100755
--- a/Lib/UserString.py
+++ b/Lib/UserString.py
@@ -50,9 +50,20 @@
             return self.__class__(other + self.data)
         else:
             return self.__class__(str(other) + self.data)
+    def __iadd__(self, other):
+        if isinstance(other, UserString):
+            self.data += other.data
+        elif isinstance(other, StringType) or isinstance(other, UnicodeType):
+            self.data += other
+        else
+            self.data += str(other)
+        return self
     def __mul__(self, n):
         return self.__class__(self.data*n)
     __rmul__ = __mul__
+    def __imull__(self, n):
+        self.data += n
+        return self
 
     # the following methods are defined in alphabetical order:
     def capitalize(self): return self.__class__(self.data.capitalize())
diff --git a/Lib/dis.py b/Lib/dis.py
index 9fc9d30..713d7aa 100644
--- a/Lib/dis.py
+++ b/Lib/dis.py
@@ -182,6 +182,11 @@
 def_op('DELETE_SLICE+2', 52)
 def_op('DELETE_SLICE+3', 53)
 
+def_op('INPLACE_ADD', 55)
+def_op('INPLACE_SUBTRACT', 56)
+def_op('INPLACE_MULTIPLY', 57)
+def_op('INPLACE_DIVIDE', 58)
+def_op('INPLACE_MODULO', 59)
 def_op('STORE_SUBSCR', 60)
 def_op('DELETE_SUBSCR', 61)
 
@@ -190,13 +195,18 @@
 def_op('BINARY_AND', 64)
 def_op('BINARY_XOR', 65)
 def_op('BINARY_OR', 66)
+def_op('INPLACE_POWER', 67)
 
 def_op('PRINT_EXPR', 70)
 def_op('PRINT_ITEM', 71)
 def_op('PRINT_NEWLINE', 72)
 def_op('PRINT_ITEM_TO', 73)
 def_op('PRINT_NEWLINE_TO', 74)
-
+def_op('INPLACE_LSHIFT', 75)
+def_op('INPLACE_RSHIFT', 76)
+def_op('INPLACE_AND', 77)
+def_op('INPLACE_XOR', 78)
+def_op('INPLACE_OR', 79)
 def_op('BREAK_LOOP', 80)
 
 def_op('LOAD_LOCALS', 82)
diff --git a/Lib/rfc822.py b/Lib/rfc822.py
index 6473149..42aac1c 100644
--- a/Lib/rfc822.py
+++ b/Lib/rfc822.py
@@ -763,6 +763,13 @@
                 newaddr.addresslist.append(x)
         return newaddr
 
+    def __iadd__(self, other):
+        # Set union, in-place
+        for x in other.addresslist:
+            if not x in self.addresslist:
+                self.addresslist.append(x)
+        return self
+
     def __sub__(self, other):
         # Set difference
         newaddr = AddressList(None)
@@ -771,6 +778,13 @@
                 newaddr.addresslist.append(x)
         return newaddr
 
+    def __isub__(self, other):
+        # Set difference, in-place
+        for x in other.addresslist:
+            if x in self.addresslist:
+                self.addresslist.remove(x)
+        return self
+
     def __getitem__(self, index):
         # Make indexing, slices, and 'in' work
         return self.addresslist[index]
diff --git a/Lib/test/output/test_augassign b/Lib/test/output/test_augassign
new file mode 100644
index 0000000..ceffd59
--- /dev/null
+++ b/Lib/test/output/test_augassign
@@ -0,0 +1,48 @@
+test_augassign
+6
+[6]
+6
+[1, 2, 3, 4, 1, 2, 3, 4]
+[1, 2, 1, 2, 3]
+1
+1
+1
+11
+1
+12
+1
+1
+13
+__add__ called
+__radd__ called
+__iadd__ called
+__sub__ called
+__rsub__ called
+__isub__ called
+__mul__ called
+__rmul__ called
+__imul__ called
+__div__ called
+__rdiv__ called
+__idiv__ called
+__mod__ called
+__rmod__ called
+__imod__ called
+__pow__ called
+__rpow__ called
+__ipow__ called
+__or__ called
+__ror__ called
+__ior__ called
+__and__ called
+__rand__ called
+__iand__ called
+__xor__ called
+__rxor__ called
+__ixor__ called
+__rshift__ called
+__rrshift__ called
+__irshift__ called
+__lshift__ called
+__rlshift__ called
+__ilshift__ called
diff --git a/Lib/test/test_augassign.py b/Lib/test/test_augassign.py
new file mode 100644
index 0000000..a01195e
--- /dev/null
+++ b/Lib/test/test_augassign.py
@@ -0,0 +1,232 @@
+
+# Augmented assignment test.
+
+x = 2
+x += 1
+x *= 2
+x **= 2
+x -= 8
+x /= 2
+x %= 12
+x &= 2
+x |= 5
+x ^= 1
+
+print x
+
+x = [2]
+x[0] += 1
+x[0] *= 2
+x[0] **= 2
+x[0] -= 8
+x[0] /= 2
+x[0] %= 12
+x[0] &= 2
+x[0] |= 5
+x[0] ^= 1
+
+print x
+
+x = {0: 2}
+x[0] += 1
+x[0] *= 2
+x[0] **= 2
+x[0] -= 8
+x[0] /= 2
+x[0] %= 12
+x[0] &= 2
+x[0] |= 5
+x[0] ^= 1
+
+print x[0]
+
+x = [1,2]
+x += [3,4]
+x *= 2
+
+print x
+
+x = [1, 2, 3]
+y = x
+x[1:2] *= 2
+y[1:2] += [1]
+
+print x
+print x is y
+
+class aug_test:
+	def __init__(self, value):
+		self.val = value
+	def __radd__(self, val):
+		return self.val + val
+	def __add__(self, val):
+		return aug_test(self.val + val)
+
+
+class aug_test2(aug_test):
+	def __iadd__(self, val):
+		self.val = self.val + val
+		return self
+
+class aug_test3(aug_test):
+	def __iadd__(self, val):
+		return aug_test3(self.val + val)
+
+x = aug_test(1)
+y = x
+x += 10
+
+print isinstance(x, aug_test)
+print y is not x 
+print x.val
+
+x = aug_test2(2)
+y = x
+x += 10
+
+print y is x
+print x.val
+
+x = aug_test3(3)
+y = x
+x += 10
+
+print isinstance(x, aug_test3)
+print y is not x
+print x.val
+
+class testall:
+
+	def __add__(self, val):
+		print "__add__ called"
+	def __radd__(self, val):
+		print "__radd__ called"
+	def __iadd__(self, val):
+		print "__iadd__ called"
+		return self
+
+	def __sub__(self, val):
+		print "__sub__ called"
+	def __rsub__(self, val):
+		print "__rsub__ called"
+	def __isub__(self, val):
+		print "__isub__ called"
+		return self
+
+	def __mul__(self, val):
+		print "__mul__ called"
+	def __rmul__(self, val):
+		print "__rmul__ called"
+	def __imul__(self, val):
+		print "__imul__ called"
+		return self
+
+	def __div__(self, val):
+		print "__div__ called"
+	def __rdiv__(self, val):
+		print "__rdiv__ called"
+	def __idiv__(self, val):
+		print "__idiv__ called"
+		return self
+
+	def __mod__(self, val):
+		print "__mod__ called"
+	def __rmod__(self, val):
+		print "__rmod__ called"
+	def __imod__(self, val):
+		print "__imod__ called"
+		return self
+
+	def __pow__(self, val):
+		print "__pow__ called"
+	def __rpow__(self, val):
+		print "__rpow__ called"
+	def __ipow__(self, val):
+		print "__ipow__ called"
+		return self
+
+	def __or__(self, val):
+		print "__or__ called"
+	def __ror__(self, val):
+		print "__ror__ called"
+	def __ior__(self, val):
+		print "__ior__ called"
+		return self
+
+	def __and__(self, val):
+		print "__and__ called"
+	def __rand__(self, val):
+		print "__rand__ called"
+	def __iand__(self, val):
+		print "__iand__ called"
+		return self
+
+	def __xor__(self, val):
+		print "__xor__ called"
+	def __rxor__(self, val):
+		print "__rxor__ called"
+	def __ixor__(self, val):
+		print "__ixor__ called"
+		return self
+
+	def __rshift__(self, val):
+		print "__rshift__ called"
+	def __rrshift__(self, val):
+		print "__rrshift__ called"
+	def __irshift__(self, val):
+		print "__irshift__ called"
+		return self
+
+	def __lshift__(self, val):
+		print "__lshift__ called"
+	def __rlshift__(self, val):
+		print "__rlshift__ called"
+	def __ilshift__(self, val):
+		print "__ilshift__ called"
+		return self
+
+x = testall()
+x + 1
+1 + x
+x += 1
+
+x - 1
+1 - x
+x -= 1
+
+x * 1
+1 * x
+x *= 1
+
+x / 1
+1 / x
+x /= 1
+
+x % 1
+1 % x
+x %= 1
+
+x ** 1
+1 ** x
+x **= 1
+
+x | 1
+1 | x
+x |= 1
+
+x & 1
+1 & x
+x &= 1
+
+x ^ 1
+1 ^ x
+x ^= 1
+
+x >> 1
+1 >> x
+x >>= 1
+
+x << 1
+1 << x
+x <<= 1
+