diff --git a/setup.py b/setup.py
index c44870e..65164dc 100644
--- a/setup.py
+++ b/setup.py
@@ -96,7 +96,8 @@ def run(self):
         "msgpack>=0.5",
         "oscrypto",
         "paho-mqtt>=1.3",
-        "requests"
+        "requests",
+        "cffi"  # avoids oscrypto error: "oscrypto._ffi.FFIEngineError: Error initializing ctypes"
     ],
 
     tests_require=TEST_REQUIREMENTS,