diff --git a/pandas/stats/ols.py b/pandas/stats/ols.py
index 9b2bf58909f63..9454ac75d4ef6 100644
--- a/pandas/stats/ols.py
+++ b/pandas/stats/ols.py
@@ -538,7 +538,7 @@ def summary(self):
 
         f_stat = results['f_stat']
 
-        bracketed = ['<%s>' % c for c in results['beta'].index]
+        bracketed = ['<%s>' %str(c) for c in results['beta'].index]
 
         formula = StringIO()
         formula.write(bracketed[0])