Index: Lib/datetime.py
===================================================================
--- Lib/datetime.py	(revision 83213)
+++ Lib/datetime.py	(working copy)
@@ -1779,24 +1779,31 @@
 
     # Sentinel value to disallow None
     _Omitted = object()
-    def __init__(self, offset, name=_Omitted):
-        if name is self._Omitted:
+    def __new__(cls, offset, name=_Omitted):
+        if not isinstance(offset, timedelta):
+            raise TypeError("offset must be a timedelta")
+        if name is cls._Omitted:
+            if not offset:
+                return cls.utc
             name = None
         elif not isinstance(name, str):
             raise TypeError("name must be a string")
-        if isinstance(offset, timedelta):
-            if self._minoffset <= offset <= self._maxoffset:
-                if (offset.microseconds != 0 or
-                    offset.seconds % 60 != 0):
-                    raise ValueError("offset must be whole"
-                                    " number of minutes")
-                self._offset = offset
-            else:
-                raise ValueError("offset out of range")
-        else:
-            raise TypeError("offset must be timedelta")
+        if not cls._minoffset <= offset <= cls._maxoffset:
+            raise ValueError("offset must be a timedelta"
+                             " strictly between -timedelta(hours=24) and"
+                             " timedelta(hours=24).")
+        if (offset.microseconds != 0 or
+            offset.seconds % 60 != 0):
+            raise ValueError("offset must be a timedelta"
+                             " representing a whole number of minutes")
+        return cls._create(offset, name)
 
+    @classmethod
+    def _create(cls, offset, name=None):
+        self = tzinfo.__new__(cls)
+        self._offset = offset
         self._name = name
+        return self
 
     def __getinitargs__(self):
         """pickle support"""
@@ -1874,9 +1881,9 @@
         minutes = rest // timedelta(minutes=1)
         return 'UTC{}{:02d}:{:02d}'.format(sign, hours, minutes)
 
-timezone.utc = timezone(timedelta(0))
-timezone.min = timezone(timezone._minoffset)
-timezone.max = timezone(timezone._maxoffset)
+timezone.utc = timezone._create(timedelta(0))
+timezone.min = timezone._create(timezone._minoffset)
+timezone.max = timezone._create(timezone._maxoffset)
 
 """
 Some time zone algebra.  For a datetime x, let
Index: Lib/test/datetimetester.py
===================================================================
--- Lib/test/datetimetester.py	(revision 83213)
+++ Lib/test/datetimetester.py	(working copy)
@@ -176,7 +176,9 @@
 
 
     def test_constructor(self):
-        self.assertEqual(timezone.utc, timezone(timedelta(0)))
+        self.assertIs(timezone.utc, timezone(timedelta(0)))
+        self.assertIsNot(timezone.utc, timezone(timedelta(0), 'UTC'))
+        self.assertEqual(timezone.utc, timezone(timedelta(0), 'UTC'))
         # invalid offsets
         for invalid in [timedelta(microseconds=1), timedelta(1, 1),
                         timedelta(seconds=1), timedelta(1), -timedelta(1)]:
Index: Modules/_datetimemodule.c
===================================================================
--- Modules/_datetimemodule.c	(revision 83213)
+++ Modules/_datetimemodule.c	(working copy)
@@ -783,14 +783,15 @@
     PyObject *name;
 } PyDateTime_TimeZone;
 
-PyObject *PyDateTime_TimeZone_UTC;
+/* The interned UTC timezone instance */ 
+static PyObject *PyDateTime_TimeZone_UTC;
 
 /* Create new timezone instance checking offset range.  This
    function does not check the name argument.  Caller must assure
    that offset is a timedelta instance and name is either NULL
    or a unicode object. */
 static PyObject *
-new_timezone(PyObject *offset, PyObject *name)
+create_timezone(PyObject *offset, PyObject *name)
 {
     PyDateTime_TimeZone *self;
     PyTypeObject *type = &PyDateTime_TimeZoneType;
@@ -823,6 +824,22 @@
     return (PyObject *)self;
 }
 
+static int delta_bool(PyDateTime_Delta *self);
+
+static PyObject *
+new_timezone(PyObject *offset, PyObject *name)
+{
+    assert(offset != NULL);
+    assert(PyDelta_Check(offset));
+    assert(name == NULL || PyUnicode_Check(name));
+
+    if (name == NULL && delta_bool((PyDateTime_Delta *)offset) == 0) {
+        Py_INCREF(PyDateTime_TimeZone_UTC);
+        return PyDateTime_TimeZone_UTC;
+    }
+    return create_timezone(offset, name);
+}
+
 /* ---------------------------------------------------------------------------
  * tzinfo helpers.
  */
@@ -5199,7 +5216,7 @@
     delta = new_delta(0, 0, 0, 0);
     if (delta == NULL)
         return NULL;
-    x = new_timezone(delta, NULL);
+    x = create_timezone(delta, NULL);
     Py_DECREF(delta);
     if (x == NULL || PyDict_SetItemString(d, "utc", x) < 0)
         return NULL;
@@ -5208,7 +5225,7 @@
     delta = new_delta(-1, 60, 0, 1); /* -23:59 */
     if (delta == NULL)
         return NULL;
-    x = new_timezone(delta, NULL);
+    x = create_timezone(delta, NULL);
     Py_DECREF(delta);
     if (x == NULL || PyDict_SetItemString(d, "min", x) < 0)
         return NULL;
@@ -5217,7 +5234,7 @@
     delta = new_delta(0, (23 * 60 + 59) * 60, 0, 0); /* +23:59 */
     if (delta == NULL)
         return NULL;
-    x = new_timezone(delta, NULL);
+    x = create_timezone(delta, NULL);
     Py_DECREF(delta);
     if (x == NULL || PyDict_SetItemString(d, "max", x) < 0)
         return NULL;