A knee rehabilitation exercise device comprised of a right and left leg brace, a rear knee strap, an upper leg strap assembly, a lower leg strap assembly, a portable rear brace assembly and an elastic resistance band. The left and right leg brace members are each comprised of an upper member and a lower member rotatably pinned together at the area of the knee joint. The left and right leg braces are attached to the upper and lower leg strap assembly. The rear knee strap is attached to the left and right leg braces at the knee joint. When a user places the elastic band onto L hooks mounted on the upper and lower strap assembly and the rear brace assembly is placed between the rear of the user's knee and the elastic band, a resistive stretching is caused when the user straightens his leg which exercises and strengthens the user's leg muscles in the area of the knee joint.