diff --git a/.travis.yml b/.travis.yml
index ea12849..ceef099 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -35,7 +35,7 @@ before_install:
   - sudo apt-get install gfortran
 # Install packages
 install:
-  - conda install --yes python=$TRAVIS_PYTHON_VERSION numpy scipy pytest numdifftools
+  - conda install --yes python=$TRAVIS_PYTHON_VERSION numpy scipy pytest numdifftools matplotlib
   - pip install coveralls
 #  - python setup.py build
   - python setup.py install
diff --git a/requirements.txt b/requirements.txt
index 260dceb..e8114e1 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -3,4 +3,5 @@ six
 numpy>=1.4
 numdifftools>=0.2
 scipy>=0.9
+matplotlib