diff --git a/.travis.yml b/.travis.yml
index 442264ab..791631b4 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,8 +8,7 @@
 language: python
 sudo: false
 cache:
-  directories:
-    - $HOME/.cache/pip
+  - pip
 addons:
   apt:
     packages:
@@ -28,14 +27,14 @@ notifications:
     on_start: false     # default: false
 
 python:
-- 2.6
-- 2.7
-- 3.2
-- 3.3
-- 3.4
+  - 2.6
+  - 2.7
+  - 3.2
+  - 3.3
+  - 3.4
 
 before_install:
-    - sudo apt-get update; true
+    - pip install --upgrade pip
     - source tools/travis_before_install.sh
 
     - which python; python --version
@@ -43,8 +42,7 @@ before_install:
     - tools/build_versions.py
 
 install:
-    - python setup.py build_ext --inplace
-    - python setup.py install
+    - python setup.py develop
 
 script: tools/travis_script.sh
 
diff --git a/optional_requirements.txt b/optional_requirements.txt
new file mode 100644
index 00000000..cd98c274
--- /dev/null
+++ b/optional_requirements.txt
@@ -0,0 +1,5 @@
+PySide; python_version != '2.7'
+imread; python_version != '3.2'
+SimpleITK; python_version != '3.2' and python_version != '3.4'
+astropy
+tifffile
diff --git a/tools/travis_script.sh b/tools/travis_script.sh
index 3c459ac7..27f0615e 100755
--- a/tools/travis_script.sh
+++ b/tools/travis_script.sh
@@ -20,6 +20,9 @@ section_end "Flake8.test"
 
 section "Install.optional.dependencies"
 
+# Install most of the optional packages
+pip install --retries 3 -q -r ./optional_requirements.txt $WHEELHOUSE
+
 # Install Qt and then update the Matplotlib settings
 if [[ $PY == 2.7* ]]; then
     # http://stackoverflow.com/a/9716100
@@ -37,30 +40,13 @@ if [[ $PY == 2.7* ]]; then
     done
 
 else
-    retry pip install -q PySide $WHEELHOUSE
     python ~/venv/bin/pyside_postinstall.py -install
-fi 
-
-# Install imread from wheelhouse if available (not 3.2)
-if [[ $PY != 3.2 ]]; then
-    retry pip install -q $WHEELHOUSE
 fi
 
-# Install SimpleITK from wheelhouse if available (not 3.2 or 3.4)
-if [[ $PY =~ 3\.[24] ]]; then
-    echo "SimpleITK unavailable on $PY"
-else
-    retry pip install -q SimpleITK $WHEELHOUSE
-fi
-
-retry pip install -q astropy $WHEELHOUSE
-
 if [[ $PY == 2.* ]]; then
     retry pip install -q pyamg
 fi
 
-retry pip install -q tifffile
-
 section_end "Install.optional.dependencies"