Violence in the workplace is a serious public health problem. Yet, to date, little has been documented relevant to non-fatal events associated with physical assault. The aim of the present study was to identify the magnitude of work-related physical assault in Minnesota and to identify potential risk factors; both fatal and non-fatal cases were included. Minnesota workers' compensation records, relevant to assault, were used to identify 712 cases involving more than three days of lost work time for 1992; six homicide cases were included. Assault rates were calculated by industry and occupation. Women had an assault rate twice that of men (51 versus 26 per 100,000 workers). Workers in industries of social services (340), health services (202), and transportation (914) had the highest rates of assault per 100,000 full-time employees. The fact that in addition to overall workers' compensation costs of $1.6 million, the average lost time for closed compensated cases was 54 days (median, 14 days) and time to reach maximum medical improvement for 44% of the cases reporting was 156 days (median, 83 days), indicates a major problem. The findings suggest that specific groups of workers are at risk for physical assault on the job. Further research is essential to identify specific risk factors that will enable the development of appropriate prevention strategies.