diff --git a/supervised/preprocessing/preprocessing_utils.py b/supervised/preprocessing/preprocessing_utils.py
index f4896919..c314e4d3 100644
--- a/supervised/preprocessing/preprocessing_utils.py
+++ b/supervised/preprocessing/preprocessing_utils.py
@@ -111,6 +111,8 @@ def is_na(x):
     @staticmethod
     def get_most_frequent(x):
         a = x.value_counts()
+        if a.empty:
+            return None
         first = sorted(dict(a).items(), key=lambda x: -x[1])[0]
         return first[0]