diff --git a/requirements.txt b/requirements.txt
index 3034dfa280..6a075f1fb5 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,8 @@ seaborn
 h5py
 tables
 tqdm
-scikit-learn>=0.19.1
+# exclude buggy versions
+scikit-learn >= 0.19.1, != 0.21.0, != 0.21.1
 statsmodels
 patsy
 networkx