diff --git a/services/topic_classification/requirements.txt b/services/topic_classification/requirements.txt
index 71c1802..f91bdbd 100644
--- a/services/topic_classification/requirements.txt
+++ b/services/topic_classification/requirements.txt
@@ -2,7 +2,7 @@ django==1.10.4
 scikit-learn==0.18.1
 numpy==1.11.1
 scipy==0.18.1
-nltk==3.2.1
+nltk==3.4.5
 neo4jrestclient==2.1.1
 bllipparser==2016.9.11
 whitenoise==3.3.0