diff --git a/.travis.yml b/.travis.yml
index 6f07b60..5dc5d3f 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=$TRAVIS_PYTHON_VERSION numpy scipy pytest
+  - conda install --yes python=$TRAVIS_PYTHON_VERSION numpy scipy pytest numdifftools
   - pip install coveralls
   - python setup.py build
   - python setup.py install