A complete system to quantify three-dimensional human movement kinematics was developed and initial accuracy testing was completed. This video-based system incorporates a video processor produced by Motion Analysis Corporation to edge-detect markers in a calibrated space, a SUN computer work station to receive data from the video processor, and appropriate software for analysis of the data. A series of tests was performed to compare static and dynamic accuracy of this video-based system to that reported of other video and film-based systems. The mean absolute errors for the static testing were 4.0 mm in the X direction, 2.5 mm in the Y direction, and 5.4 mm in the Z direction, with standard deviations of 4.0, 1.8, and 5.9 mm respectively. The mean absolute errors for the static testing were 11.1, 2.6, and 17.6 mm in the X, Y, and Z directions, respectively, with standard deviations of 0.4, 0.5, and 1.1 mm. These errors are comparable to those of other video-based systems but are slightly higher than those found with film-based systems.