diff --git a/letsencrypt/client/network.py b/letsencrypt/client/network.py
index de6db575b..2719583c3 100644
--- a/letsencrypt/client/network.py
+++ b/letsencrypt/client/network.py
@@ -11,6 +11,9 @@ from letsencrypt.acme import messages
 from letsencrypt.client import errors
 
 
+# https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning
+requests.packages.urllib3.contrib.pyopenssl.inject_into_urllib3()
+
 logging.getLogger("requests").setLevel(logging.WARNING)
 
 
diff --git a/setup.py b/setup.py
index 520147433..45873e9e8 100755
--- a/setup.py
+++ b/setup.py
@@ -32,7 +32,9 @@ install_requires = [
     'ConfArgParse',
     'jsonschema',
     'mock',
+    'ndg-httpsclient',  # urllib3 InsecurePlatformWarning (#304)
     'psutil>=2.1.0',  # net_connections introduced in 2.1.0
+    'pyasn1',  # urllib3 InsecurePlatformWarning (#304)
     'pycrypto',
     'PyOpenSSL',
     'python-augeas',