diff --git a/README.md b/README.md
index 1227198bef04c6408950bce7c2aa1fd9c6090804..62efbf611a971b1247efa7e5078a3035b98e3e29 100644
--- a/README.md
+++ b/README.md
@@ -13,7 +13,16 @@ The MHCflurry predictors are implemented in Python using [keras](https://keras.i
 
 ## Setup
 
-Install the package:
+To configure keras, the neural network library used by MHCflurry, you'll need to set an environment variable in your shell:
+
+```
+export KERAS_BACKEND=theano
+```
+
+If you're familiar with keras, you may also try using the tensorflow backend. MHCflurry is currently tested using theano, however.
+ 
+
+Now install the package:
 
 ```
 pip install mhcflurry
diff --git a/requirements.txt b/requirements.txt
index 0893a3a06325f9217c98a4135e79ad53253c44e3..78a52a934f1732bc8eb3d459bafa9c01f1d54728 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,7 +2,7 @@ numpy>= 1.11
 pandas>=0.13.1
 appdirs
 theano>=0.8.2
-keras
+keras==1.1.0
 fancyimpute>=0.0.12
 scikit-learn
 h5py
diff --git a/setup.py b/setup.py
index 796b1ccb4d4fb5b3c56cccf4192609217d79a46a..07adad407a940d14046cf4eb03e04bc1ac30f516 100644
--- a/setup.py
+++ b/setup.py
@@ -76,7 +76,7 @@ if __name__ == '__main__':
             'pandas>=0.13.1',
             'appdirs',
             'theano>=0.8.2',
-            'keras',
+            'keras==1.1.0',
             'fancyimpute>=0.0.12',
             'scikit-learn',
             'h5py',