There is little information available of the costs of upper extremity cumulative trauma disorders. Cost data were collected from computerized records of the Liberty Mutual Insurance Company for upper extremity cumulative trauma disorder workers' compensation claims (N = 6,067) and for all claims (N = 731,087) initiated from 45 states during 1989. The data were not analyzed until July 1992, allowing more accurate "closing cost" data to be used in the analysis. Upper extremity cumulative trauma disorder cases represented 0.83% of all claims and 1.64% of all claims costs. The mean cost per case for upper extremity cumulative trauma disorders was $8070; median cost per case was $824. Medical costs represented 32.9% of the total costs; indemnity costs were 65.1%. The total compensable cost for upper extremity cumulative trauma disorders in the United States was estimated to be $563 million.