Index: Doc/library/decimal.rst
===================================================================
--- Doc/library/decimal.rst	(revision 81892)
+++ Doc/library/decimal.rst	(working copy)
@@ -392,7 +392,16 @@
       ``Decimal('321e+5').adjusted()`` returns seven.  Used for determining the
       position of the most significant digit with respect to the decimal point.
 
+   .. method:: as_integer_ratio()
 
+      Return a pair ``(n, d)`` of integers that represent the given
+      :class:`Decimal` instance as a fraction, in lowest terms::
+
+	  >>> Decimal('-3.14').as_integer_ratio()
+	  (-157, 50)
+
+      .. versionadded:: 3.2
+
    .. method:: as_tuple()
 
       Return a :term:`named tuple` representation of the number:
Index: Lib/decimal.py
===================================================================
--- Lib/decimal.py	(revision 81892)
+++ Lib/decimal.py	(working copy)
@@ -965,6 +965,67 @@
         """
         return DecimalTuple(self._sign, tuple(map(int, self._int)), self._exp)
 
+    def as_integer_ratio(self):
+        """Return a pair (n, d) such that self == n / d.
+
+        >>> Decimal('3.14').as_integer_ratio()
+        (157, 50)
+        >>> Decimal('-123e5').as_integer_ratio()
+        (-12300000, 1)
+        >>> Decimal('0.00').as_integer_ratio()
+        (0, 1)
+        >>> Decimal('Infinity').as_integer_ratio()
+        Traceback (most recent call last):
+          ...
+          ...
+          ...
+        OverflowError: Cannot pass infinity to decimal.as_integer_ratio.
+        >>> Decimal('NaN').as_integer_ratio()
+        Traceback (most recent call last):
+          ...
+          ...
+          ...
+        ValueError: Cannot pass NaN to decimal.as_integer_ratio.
+
+        """
+        if self._is_special:
+            if self.is_nan():
+                raise ValueError("Cannot pass NaN "
+                                 "to decimal.as_integer_ratio.")
+            else:
+                raise OverflowError("Cannot pass infinity "
+                                    "to decimal.as_integer_ratio.")
+
+        if not self:
+            return 0, 1
+
+        # Find n, d in lowest terms such that abs(self) == n / d;
+        # we'll deal with the sign later.
+        n = int(self._int)
+        if self._exp >= 0:
+            # self is an integer.
+            n, d = n * 10**self._exp, 1
+        else:
+            # Find d2, d5 such that abs(self) = n / (2**d2 * 5**d5).
+            d5 = -self._exp
+            while d5 > 0 and n % 5 == 0:
+                n //= 5
+                d5 -= 1
+
+            # (n & -n).bit_length() - 1 counts trailing zeros in binary
+            # representation of n (provided n is nonzero).
+            d2 = -self._exp
+            shift2 = min((n & -n).bit_length() - 1, d2)
+            if shift2:
+                n >>= shift2
+                d2 -= shift2
+
+            d = 5**d5 << d2
+
+        if self._sign:
+            n = -n
+        return n, d
+
     def __repr__(self):
         """Represents the number as an instance of Decimal."""
         # Invariant:  eval(repr(d)) == d
Index: Lib/test/test_decimal.py
===================================================================
--- Lib/test/test_decimal.py	(revision 81892)
+++ Lib/test/test_decimal.py	(working copy)
@@ -31,6 +31,7 @@
 import pickle, copy
 import unittest
 from decimal import *
+from fractions import gcd
 import numbers
 from test.support import run_unittest, run_doctest, is_resource_enabled
 from test.support import check_warnings
@@ -1566,6 +1567,39 @@
         d = Decimal( (1, (0, 2, 7, 1), 'F') )
         self.assertEqual(d.as_tuple(), (1, (0,), 'F'))
 
+    def test_as_integer_ratio(self):
+        # exceptional cases
+        self.assertRaises(OverflowError,
+                          Decimal.as_integer_ratio, Decimal('inf'))
+        self.assertRaises(OverflowError,
+                          Decimal.as_integer_ratio, Decimal('-Inf'))
+        self.assertRaises(ValueError,
+                          Decimal.as_integer_ratio, Decimal('-nan'))
+        self.assertRaises(ValueError,
+                          Decimal.as_integer_ratio, Decimal('snAN'))
+
+        for exp in range(-4, 2):
+            for coeff in range(1000):
+                for sign in '+', '-':
+                    d = Decimal('%s%dE%d' % (sign, coeff, exp))
+                    pq = d.as_integer_ratio()
+                    p, q = pq
+
+                    # check return type
+                    self.assertIsInstance(pq, tuple)
+                    self.assertIsInstance(p, int)
+                    self.assertIsInstance(q, int)
+
+                    # check normalization:  q should be positive;
+                    # p should be relatively prime to q.
+                    self.assertGreater(q, 0)
+                    self.assertEqual(gcd(p, q), 1)
+
+                    # check that p/q actually gives the correct value
+                    self.assertEqual(Decimal(p) / Decimal(q), d)
+
+
+
     def test_immutability_operations(self):
         # Do operations and check that it didn't change change internal objects.