To most closely simulate the pe1formance of a biological human foot, a prosthetic foot should function similarly to the biological foot: The shock absorption, propulsion, balance and dorsiflexion functions of the prosthesis should closely mirror those of the biological foot. Most prosthetic feet currently available have good absorption and propulsion abilities, and some also have good balance functions. Howeve1; most prosthetic feet lack proper imitation of the dorsiflexion phase of normal gait. Dorsiflexion is crucial to the gait pattern since most foot flexors are used during this phase. A new rolling-joint prosthetic foot (RJF) has been developed to simulate a more natural moment of resistance in the dorsiflexion phase. The pilot biomechanical study of one transtibial amputee presented here indicates improved gait pe1formance with use of the RJF.