The “Rutgers Ankle” is a Stewart platform-type haptic interface designed for use in rehabilitation. The system supplies six-DOF resistive forces in response to virtual reality-based exercises running on a host PC. The Stewart platform uses double-acting pneumatic cylinders, linear potentiometers as position sensors, and a six-DOF force sensor. The Rutgers Ankle controller contains an embedded Pentium board, pneumatic solenoid valves, valve controllers, and associated signal conditioning electronics. Communication with the host PC is over a standard RS232 line. The platform movement and output forces are transparently recorded by the host PC in a database. This database can be accessed remotely over the Internet. Thus, the Rutgers Ankle Orthopedic Rehabilitation Interface will allow patients to exercise at home while being monitored remotely by therapists. A prototype was constructed, and proof-of-concept trials were conducted at the University of Medicine and Dentistry of New Jersey. The results indicate that the system works well as a diagnostic tool. The subjective evaluation by patients was very positive. Further medical trials are needed before the system clinical efficacy in rehabilitation can be established.