diff --git a/CHANGES.md b/CHANGES.md
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,7 @@
+## Version 1.2.3.3
+
+ * Support integer-simple.
+
 ## Version 1.2.3.2
 
  * Add support for GHC 7.10 typeRepFingerprint
diff --git a/Data/Hashable/Class.hs b/Data/Hashable/Class.hs
--- a/Data/Hashable/Class.hs
+++ b/Data/Hashable/Class.hs
@@ -90,9 +90,14 @@
 #endif
 
 #ifdef VERSION_integer_gmp
+
+# if MIN_VERSION_integer_gmp(1,0,0)
+#  define MIN_VERSION_integer_gmp_1_0_0
+# endif
+
 import GHC.Exts (Int(..))
 import GHC.Integer.GMP.Internals (Integer(..))
-# if MIN_VERSION_integer_gmp(1,0,0)
+# if defined(MIN_VERSION_integer_gmp_1_0_0)
 import GHC.Exts (sizeofByteArray#)
 import GHC.Integer.GMP.Internals (BigNat(BN#))
 # endif
@@ -253,20 +258,18 @@
     hash = fromEnum
     hashWithSalt = defaultHashWithSalt
 
-#if defined(VERSION_integer_gmp)
-# if MIN_VERSION_integer_gmp(1,0,0)
+#if defined(MIN_VERSION_integer_gmp_1_0_0)
 instance Hashable BigNat where
     hashWithSalt salt (BN# ba) = hashByteArrayWithSalt ba 0 numBytes salt
                                  `hashWithSalt` size
       where
         size     = numBytes `quot` SIZEOF_HSWORD
         numBytes = I# (sizeofByteArray# ba)
-# endif
 #endif
 
 #if MIN_VERSION_base(4,8,0)
 instance Hashable Natural where
-# if MIN_VERSION_integer_gmp(1,0,0)
+# if defined(MIN_VERSION_integer_gmp_1_0_0)
     hash (NatS# n)   = hash (W# n)
     hash (NatJ# bn)  = hash bn
 
@@ -281,7 +284,7 @@
 
 instance Hashable Integer where
 #if defined(VERSION_integer_gmp)
-# if MIN_VERSION_integer_gmp(1,0,0)
+# if defined(MIN_VERSION_integer_gmp_1_0_0)
     hash (S# n)   = (I# n)
     hash (Jp# bn) = hash bn
     hash (Jn# bn) = negate (hash bn)
diff --git a/hashable.cabal b/hashable.cabal
--- a/hashable.cabal
+++ b/hashable.cabal
@@ -1,5 +1,5 @@
 Name:                hashable
-Version:             1.2.3.2
+Version:             1.2.3.3
 Synopsis:            A class for types that can be converted to a hash value
 Description:         This package defines a class, 'Hashable', for types that
                      can be converted to a hash value.  This class