diff --git a/requirements_rtd.txt b/requirements_rtd.txt
index 4ab1e8462..81c53c43e 100644
--- a/requirements_rtd.txt
+++ b/requirements_rtd.txt
@@ -17,6 +17,5 @@ bashplotlib==0.6.1
 numexpr==2.4
 sphinx-rtd-theme>=0.1.6
 numpydoc>=0.5
-cobra>=0.3.0b3
 mock>=1.0.1
 sphinxcontrib-napoleon>=0.2.8