diff --git a/pypots/classification/grud/data.py b/pypots/classification/grud/data.py
index fc23132e..3287a6f6 100644
--- a/pypots/classification/grud/data.py
+++ b/pypots/classification/grud/data.py
@@ -63,6 +63,8 @@ def __init__(
             self.empirical_mean = torch.sum(
                 self.missing_mask * self.X, dim=[0, 1]
             ) / torch.sum(self.missing_mask, dim=[0, 1])
+            # fill nan with 0, in case some features have no observations
+            self.empirical_mean = torch.nan_to_num(self.empirical_mean, 0)
 
     def _fetch_data_from_array(self, idx: int) -> Iterable:
         """Fetch data according to index.