diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py
index 81d892fba0fe2..f4a5dfa3fd29a 100644
--- a/pandas/core/indexes/multi.py
+++ b/pandas/core/indexes/multi.py
@@ -2097,7 +2097,9 @@ def _maybe_to_slice(loc):
             mask[loc] = True
             return mask
 
-        if not isinstance(key, tuple):
+        if isinstance(key, slice):
+            return key
+        elif not isinstance(key, tuple):
             loc = self._get_level_indexer(key, level=0)
             return _maybe_to_slice(loc)
 
diff --git a/pandas/tests/indexing/test_multiindex.py b/pandas/tests/indexing/test_multiindex.py
index d89c64fc5b9f8..014573cdf621d 100644
--- a/pandas/tests/indexing/test_multiindex.py
+++ b/pandas/tests/indexing/test_multiindex.py
@@ -239,6 +239,15 @@ def test_iloc_getitem_multiindex(self):
             xp = mi_labels.ix['j'].ix[:, 'j'].ix[0, 0]
         assert rs == xp
 
+        # GH8856
+        s = pd.Series(np.arange(10),
+                      pd.MultiIndex.from_product(([0, 1], list('abcde'))))
+        result = s.iloc[::4]
+        expected = pd.Series(np.array([0, 4, 8]),
+                             MultiIndex(levels=[[0, 1], list('ade')],
+                                        labels=[[0, 0, 1], [0, 2, 1]]))
+        tm.assert_series_equal(result, expected)
+
     def test_loc_multiindex(self):
 
         mi_labels = DataFrame(np.random.randn(3, 3),
@@ -278,6 +287,15 @@ def test_loc_multiindex(self):
             xp = mi_int.ix[4]
         tm.assert_frame_equal(rs, xp)
 
+        # GH8856
+        s = pd.Series(np.arange(10),
+                      pd.MultiIndex.from_product(([0, 1], list('abcde'))))
+        result = s.loc[::4]
+        expected = pd.Series(np.array([0, 4, 8]),
+                             MultiIndex(levels=[[0, 1], ['a', 'd', 'e']],
+                                        labels=[[0, 0, 1], [0, 2, 1]]))
+        tm.assert_series_equal(result, expected)
+
     def test_getitem_partial_int(self):
         # GH 12416
         # with single item