diff --git a/requirements_dev.txt b/requirements_dev.txt
index 638fb1c..fff0b8a 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -7,6 +7,6 @@ tox==2.7.0
 coverage==4.4.1
 Sphinx==1.6.3
 cryptography==2.0.3
-PyYAML==3.12
+PyYAML==3.13
 requests==2.18.4
 nose==1.3.7