diff --git a/RELEASE.rst b/RELEASE.rst
index c1fa30e23bc5a..a1bb3a252ec6e 100644
--- a/RELEASE.rst
+++ b/RELEASE.rst
@@ -202,6 +202,7 @@ pandas 0.11.0
   - Fixed bug in Timestamp(d,tz=foo) when d is date() rather then datetime() (GH2993_)
   - series.plot(kind='bar') now respects pylab color schem (GH3115_)
   - Fixed bug in reshape if not passed correct input, now raises TypeError (GH2719_)
+  - Fix NameError issue on RESO_US (GH2787_)
 
  .. _GH2758: https://github.com/pydata/pandas/issues/2758
 .. _GH2809: https://github.com/pydata/pandas/issues/2809
@@ -227,6 +228,7 @@ pandas 0.11.0
 .. _GH2751: https://github.com/pydata/pandas/issues/2751
 .. _GH2776: https://github.com/pydata/pandas/issues/2776
 .. _GH2778: https://github.com/pydata/pandas/issues/2778
+.. _GH2787: https://github.com/pydata/pandas/issues/2787
 .. _GH2793: https://github.com/pydata/pandas/issues/2793
 .. _GH2795: https://github.com/pydata/pandas/issues/2795
 .. _GH2819: https://github.com/pydata/pandas/issues/2819
diff --git a/pandas/tseries/frequencies.py b/pandas/tseries/frequencies.py
index 3bf29af8581a9..a43c80bf22158 100644
--- a/pandas/tseries/frequencies.py
+++ b/pandas/tseries/frequencies.py
@@ -34,11 +34,11 @@ class Resolution(object):
 
     @classmethod
     def get_str(cls, reso):
-        return {RESO_US: 'microsecond',
-                RESO_SEC: 'second',
-                RESO_MIN: 'minute',
-                RESO_HR: 'hour',
-                RESO_DAY: 'day'}.get(reso, 'day')
+        return {cls.RESO_US: 'microsecond',
+                cls.RESO_SEC: 'second',
+                cls.RESO_MIN: 'minute',
+                cls.RESO_HR: 'hour',
+                cls.RESO_DAY: 'day'}.get(reso, 'day')
 
 
 def get_reso_string(reso):