Using the California State Computer Mortality File, a step-by-step procedure was developed to identify work-related deaths. A search was made of death certificates using three factors: (1) injury at work, (2) injury at a work location, and (3) pertinent external-cause-of-death codes. The computer search yielded 513 deaths that were possibly work-related, of which only 466 could be confirmed as homicides at work. Only 30 percent of the 466 homicide deaths identified also were found in the logs of the State occupational safety and health agency. The average annual rate of work-related homicides was 1.5 per 100,000 workers. The male-to-female-rate ratio was 4.2 to 1. Police and security guards and persons in occupations having frequent public contact involving exchange of money, particularly in late afternoon or evening hours, were at highest risk. Controlling exposures of high-risk individuals and developing strict standards for reducing such exposures might greatly reduce assaults and thus prevent senseless loss of life in the workplace. Tabular data and 13 references. (Author abstract modified)