diff --git a/autosklearn/evaluation/train_evaluator.py b/autosklearn/evaluation/train_evaluator.py
index f19db473bf..b7f9be73d3 100644
--- a/autosklearn/evaluation/train_evaluator.py
+++ b/autosklearn/evaluation/train_evaluator.py
@@ -81,7 +81,7 @@ def subsample_indices(
     elif subsample > 1:
         raise ValueError("Subsample must not be larger than 1, but is %f" % subsample)
 
-    if subsample is not None and subsample < 1:
+    if subsample is not None and 0 <= subsample < 1:
         # Only subsample if there are more indices given to this method than
         # required to subsample because otherwise scikit-learn will complain