diff --git a/pandas/io/formats/style.py b/pandas/io/formats/style.py
index 58796aa30f0bf..20e72dd6bde91 100644
--- a/pandas/io/formats/style.py
+++ b/pandas/io/formats/style.py
@@ -364,7 +364,7 @@ def format(self, formatter, subset=None):
         >>> df = pd.DataFrame(np.random.randn(4, 2), columns=['a', 'b'])
         >>> df.style.format("{:.2%}")
         >>> df['c'] = ['a', 'b', 'c', 'd']
-        >>> df.style.format({'C': str.upper})
+        >>> df.style.format({'c': str.upper})
         """
         if subset is None:
             row_locs = range(len(self.data))