diff --git a/requirements.txt b/requirements.txt
index 1d4ac04..e8d8c5a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-nltk==3.2.1
+nltk==3.4.5
 numpy==1.11.2
 scikit-learn==0.18
 scipy==0.18.1