BACKGROUND: Robberies are the leading motive for work-related homicide and assault. Interventions to reduce robberies and related injuries have been limited to convenience stores, and evaluations have not addressed compliance as a factor in program effectiveness. SETTING/PARTICIPANTS: A total of 314 intervention and 96 control businesses were included in this intervention evaluation. INTERVENTION: The Workplace Violence Prevention Program provided a customized robbery and violence prevention program to a stratified random sample of 314 small, high-risk businesses in Los Angeles City. An additional 96 comparison businesses did not receive the intervention. The intervention included individualized consultation, printed materials, training brochures, and a video. Interventions were conducted from August 1997 through August 2000. MAIN OUTCOME MEASURES: For both intervention and comparison businesses, a comprehensive security program assessment was conducted at baseline and at 3- and 12-month follow-up visits. Crime rates in intervention and comparison businesses were examined for 12 months pre- and post-intervention with the use of police reports. RESULTS: By the second follow-up visit, compliance to the intervention program was significant for each program component. Employee training was the most frequently implemented intervention component. Neighborhood crime level, primary language spoken by the business owner, and the number of employees were all related to compliance. Although crime rates generally increased for all businesses from the pre- to post-intervention periods, businesses with high compliance to the program experienced a decrease in overall violent crime and robbery. CONCLUSIONS: Participating businesses were willing to voluntarily implement components of the intervention program, and greater implementation was related to reductions in robbery and violent crime.