diff --git a/requirements.txt b/requirements.txt
index c997a5f012..e5ee11f38f 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -22,3 +22,4 @@ pyelftools>=0.24,<=0.25
 git+https://github.com/armmbed/manifest-tool.git@v1.4.6
 pyocd>=0.14,<0.15
 icetea>=1.0.2,<1.1
+pyusb>=1.0.0