diff --git a/requirements.txt b/requirements.txt
index b6286b4..044d774 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,7 +11,7 @@ lxml==3.2.4
 matplotlib==1.3.1
 mechanize==0.2.5
 mock==1.0.1
-nltk==2.0.4
+nltk==3.4.5
 numpy==1.7.1
 openpyxl==1.7.0
 pandas==0.11.0