A surveillance study was made of work injuries caused by power and nonpower hand tools to determine industry and occupation specific associations, rates for specific tools, and nature of injuries. Workers' compensation claims were analyzed for 129,399 cases from the 1983 Bureau of Labor Statistics Supplementary Data System. There were 101,095 nonpower and 28,304 power hand tool injuries. Manufacturing showed the highest percentage of injury for both power and nonpower hand tools, followed by construction for power tools and retail trade for nonpower tools. The third highest percentage was in services industry for both tool types. Relative injury incidence was highest in agriculture followed by construction for both types of tools. Cooks and food service workers had the highest rates of nonpower hand tool injury, and construction laborers, carpenters, and lumbermen had the highest power hand tool injury rates. Hand knives were prominently associated with nonpower tool injuries, particularly in food preparation and farm labor. Saws were prominently associated with power tool injuries, accounting for large proportions of injuries to lumbermen, carpenters, and other laborers. Acute upper extremity trauma was the most common type of injury, but musculoskeletal injuries such as sprains and strains and inflamed joints were reported in 24 percent of cases. The authors conclude that hand tools contribute to acute traumatic and musculoskeletal injuries and that nonpower and power tools pose different risks. Future directions for research and application of preventive measures were recommended.