ABSTRACT: Persons who have had bilateral lower-limb amputations, especially transfemoral amputation, must use biomechanical compensations to ambulate. Compensations during gait produce abnormal loads on the body and may reduce efficiency. Recent prosthetic advances have attempted to mimic the lost musculature by adding power to knee and ankle systems. A patient with bilateral amputations (right transtibial, left transfemoral) was evaluated 10 months after injury. The patient initially presented wearing a passive prosthetic system and was then fit with a powered prosthetic system and allowed to acclimate for 1 month. Kinematic and kinetic data were collected while the patient walked overground wearing both systems. The patient showed greater symmetry of step length, decreased vertical ground reaction force, and increased limb transition work using the powered system. Biomechanical variables showed some improvements when using a powered prosthetic system, which may indicate increased mechanical efficiency and decreased lower-limb loading.