Abstract: A passive motion exerciser for simultaneously flexing the hip and knee joints of a human leg has a base portion with an inclined guide member positionable parallel to a line extending through the ankle and hip joints of the leg, a reversible motor-driven drive member movable upwardly and downwardly along the inclined guide member, and an elongated leg support frame structure securable to the leg and longitudinally adjustable to fit legs of varying lengths. The support frame structure has a first end portion positionable adjacent the ankle joint, a second end portion positionable between the knee and hip joint, and a pivoted intermediate portion positionable adjacent the knee joint. A connecting member is attached to the guide member for movement therealong parallel to the drive member and is connected to the first outer end portion of the support frame structure. The second outer end portion of the support frame structure is pivotally interconnected to the drive member by a cam-driven linkage structure.