The objectives of this intervention were to introduce measures that could reduce levels of drug use at clubs. Doormen were trained in recognizing signs of drug use impairment to be able to stop drug use and impaired patrons from entering the premises. The study included 28 trendy nightclubs in Stockholm, Sweden, that used doormen to screen patrons. Data were collected at pretest when 40 entry attempts were made (2003) and posttest (2004) when 48 attempts were made. At follow-up, the doormen intervened in 27% of the attempts, a significant improvement compared to the intervention rate of 7.5% at baseline.Conclusion: The results indicate that the intervention has had effect on doormen's behavior. However, in the majority of the attempted visits, the doormen still did not intervene.