diff --git a/pandas/core/index.py b/pandas/core/index.py
index c64e181f4c721..9344e849981c9 100644
--- a/pandas/core/index.py
+++ b/pandas/core/index.py
@@ -2,18 +2,18 @@
 import datetime
 import warnings
 import operator
-
 from functools import partial
-from pandas.compat import range, zip, lrange, lzip, u, reduce, filter, map
-from pandas import compat
-import numpy as np
-
 from sys import getsizeof
+
+import numpy as np
 import pandas.tslib as tslib
 import pandas.lib as lib
 import pandas.algos as _algos
 import pandas.index as _index
 from pandas.lib import Timestamp, Timedelta, is_datetime_array
+
+from pandas.compat import range, zip, lrange, lzip, u, map
+from pandas import compat
 from pandas.core.base import PandasObject, FrozenList, FrozenNDArray, IndexOpsMixin, _shared_docs, PandasDelegate
 from pandas.util.decorators import (Appender, Substitution, cache_readonly,
                                     deprecate, deprecate_kwarg)
@@ -26,6 +26,9 @@
 from pandas.core.config import get_option
 from pandas.io.common import PerformanceWarning
 
+
+
+
 # simplify
 default_pprint = lambda x, max_seq_items=None: com.pprint_thing(x,
                                                                 escape_chars=('\t', '\r', '\n'),
@@ -973,7 +976,9 @@ def _convert_list_indexer(self, keyarr, kind=None):
         and we have a mixed index (e.g. number/labels). figure out
         the indexer. return None if we can't help
         """
-        if (kind is None or kind in ['iloc','ix']) and (is_integer_dtype(keyarr) and not self.is_floating()):
+        if (kind is None or kind in ['iloc', 'ix']) and (
+            is_integer_dtype(keyarr) and not self.is_floating() and not com.is_period_arraylike(keyarr)):
+
             if self.inferred_type != 'integer':
                 keyarr = np.where(keyarr < 0,
                                   len(self) + keyarr, keyarr)
diff --git a/pandas/tests/test_index.py b/pandas/tests/test_index.py
index 36bc0755f9a6a..d9c08a3c54947 100644
--- a/pandas/tests/test_index.py
+++ b/pandas/tests/test_index.py
@@ -3221,6 +3221,14 @@ def test_repeat(self):
         self.assert_index_equal(res, exp)
         self.assertEqual(res.freqstr, 'D')
 
+    def test_period_index_indexer(self):
+
+        #GH4125
+        idx = pd.period_range('2002-01','2003-12', freq='M')
+        df = pd.DataFrame(pd.np.random.randn(24,10), index=idx)
+        self.assert_frame_equal(df, df.ix[idx])
+        self.assert_frame_equal(df, df.ix[list(idx)])
+
 
 class TestTimedeltaIndex(DatetimeLike, tm.TestCase):
     _holder = TimedeltaIndex