diff --git a/dictdiffer/utils.py b/dictdiffer/utils.py
index 6816a03..3b1c3eb 100644
--- a/dictdiffer/utils.py
+++ b/dictdiffer/utils.py
@@ -264,10 +264,19 @@ def are_different(first, second, tolerance):
         return False
 
     first_is_nan, second_is_nan = bool(first != first), bool(second != second)
+    first_is_inf, second_is_inf = first == float('inf'), second == float('inf')
+    first_is_ninf = first == float('-inf')
+    second_is_ninf = second == float('-inf')
 
     if first_is_nan or second_is_nan:
         # two 'NaN' values are not different (see issue #114)
         return not (first_is_nan and second_is_nan)
+    if first_is_inf or second_is_inf:
+        # two 'inf' values are not different
+        return not (first_is_inf and second_is_inf)
+    if first_is_ninf or second_is_ninf:
+        # two '-inf' values are not different
+        return not (first_is_ninf and second_is_ninf)
     elif isinstance(first, num_types) and isinstance(second, num_types):
         # two numerical values are compared with tolerance
         return abs(first-second) > tolerance * max(abs(first), abs(second))
diff --git a/tests/test_dictdiffer.py b/tests/test_dictdiffer.py
index 205f546..b9cea33 100644
--- a/tests/test_dictdiffer.py
+++ b/tests/test_dictdiffer.py
@@ -277,6 +277,35 @@ def test_numpy_nan(self):
         result = list(diff(first, second))
         assert result == []
 
+    def test_inf(self):
+        first = {'a': [1.0, 2.0, 3.0, 4.0]}
+        second = {'a': [1.0, 2.0, 3.0, float('inf')]}
+        diffed = next(diff(first, second))
+        assert ('change', ['a', 3], (4, float('inf'))) == diffed
+
+        first = {'a': [1.0, 2.0, 3.0, 4.0]}
+        second = {'a': [1.0, 2.0, 3.0, float('-inf')]}
+        diffed = next(diff(first, second))
+        assert ('change', ['a', 3], (4, float('-inf'))) == diffed
+
+        first = {'a': [1.0, 2.0, 3.0, float('inf')]}
+        second = {'a': [1.0, 2.0, 3.0, float('inf')]}
+        result = list(diff(first, second))
+        assert result == []
+
+        first = {'a': [1.0, 2.0, 3.0, float('inf')]}
+        second = {'a': [1.0, 2.0, 3.0, float('-inf')]}
+        diffed = next(diff(first, second))
+        assert ('change', ['a', 3], (float('inf'), float('-inf'))) == diffed
+
+    @unittest.skipIf(not HAS_NUMPY, 'NumPy is not installed')
+    def test_numpy_inf(self):
+        import numpy as np
+        first = {'a': [1.0, 2.0, 3.0, 4.0]}
+        second = {'a': [1.0, 2.0, 3.0, np.float64('inf')]}
+        diffed = next(diff(first, second))
+        assert ('change', ['a', 3], (4, np.float64('inf'))) == diffed
+
     def test_unicode_keys(self):
         first = {u'привет': 1}
         second = {'hello': 1}