diff --git a/filterpy/kalman/EKF.py b/filterpy/kalman/EKF.py
index 22b9de8..35abc3d 100644
--- a/filterpy/kalman/EKF.py
+++ b/filterpy/kalman/EKF.py
@@ -86,7 +86,7 @@ def predict_update(self, z, HJacobian, Hx, args=(), hx_args=(), u=0):
             variable.
 
         hx_args : tuple, optional, default (,)
-            arguments to be passed into HJacobian after the required state
+            arguments to be passed into Hx after the required state
             variable.
 
         u : np.array or scalar