Wheelchair ergometer testing is used to characterize wheelchair propulsion mechanics. The reliability of kinematic and kinetic measures has not been investigated for wheelchair ergometer testing. In this study, test-retest reliability of biomechanical measurements on a wheelchair ergometer was determined during a submaximal endurance test. Ten nondisabled subjects (seven male, three female), inexperienced in wheelchair propulsion, completed three separate submaximal fatigue tests. An instrumented wheelchair ergometer was used to measure handrim kinetics while three-dimensional kinematic data were collected. Analysis of variance was used to determine if measurement differences existed across the tests. Intraclass correlation coefficients (ICC) were calculated to determine the reliability of the measurements. The majority of handrim and temporal variables were found to be reliable. Joint kinematic variables were less reliable, especially those involving wrist movements in the fatigued state. It was concluded that most biomechanical variables obtained during wheelchair ergometry were reliable.