A steering mechanism is used as part of a medical device such as a catheter or an endoscope to allow movement of a steerable distal portion of the catheter or endoscope. The mechanism can include a elongate housing adapted to be coupled to the steerable portion of the medical device and an actuation system including an actuator, a first cam, and a second cam. The actuator can move the first cam between a first position and a second position along a first axis (or about a second axis different than the first axis) to move the steerable portion of the medical device along a first plane. The actuator can move the second cam between a first position and a second position along the second axis (or about the first axis) to move the steerable portion of the medical device along a second plane different than the first plane.