diff --git a/category_encoders/utils.py b/category_encoders/utils.py
index 6f8e62e7..7e617f1f 100644
--- a/category_encoders/utils.py
+++ b/category_encoders/utils.py
@@ -18,7 +18,7 @@ def convert_cols_to_list(cols):
         return list(cols)
     elif isinstance(cols, tuple):
         return list(cols)
-    elif pd.api.types.is_categorical(cols):
+    elif pd.api.types.is_categorical_dtype(cols):
         return cols.astype(object).tolist()
 
     return cols