diff --git a/requirements_dev.txt b/requirements_dev.txt
index 088eb4f..58a2f0c 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -5,7 +5,7 @@ tox==2.9.1
 flake8==3.5.0
 Sphinx==1.7.2
 coverage==4.5.1
-PyYAML==3.12
+PyYAML==4.1
 pytest==3.5.0
 pytest-cov==2.5.1
 pytest-runner==4.2