diff --git a/requirements.txt b/requirements.txt
index cb725eb..e40159d 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ numpy
 matplotlib
 scipy
 progressbar
-emcee
+emcee==3.1.6
 pyyaml
 jinja2
 cython
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 1ace67f..f620799 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -1,7 +1,7 @@
 numpy
 scipy
 progressbar
-emcee
+emcee==3.1.6
 pyyaml
 jinja2
 cython