OBJECTIVE Brief intervention for excessive alcohol consumption is effective yet not implemented widely. Alcohol misuse is implicated in unsafe sex and sexually transmitted infections and is common in clients of sexual health services. Our aims were to assess feasibility, acceptability and effectiveness of screening and brief intervention for risky alcohol consumption by a nurse in a sexual health clinic. METHODS Patients completed the AUDIT questionnaire on handheld computers. Those scoring >or=8 on AUDIT were asked to participate in the study and the 3 months' follow-up and were randomised to intervention or control groups. The Drink-less package (based on WHO validated methods) was used to implement the brief intervention by a trained registered nurse. RESULTS Of 519 (87%) who completed screening, 204 (39%) scored >or=8 on AUDIT (eligible), 184 agreed to follow-up and 133 completed it. At follow-up, both groups showed significant reductions in AUDIT scores. Mean scores decreased from 13.7 to 11.5 (control group) and 14.0 to 10.7 (intervention group); most (94%) recalled the intervention and 62% reported reducing drinking compared with 47% of controls (p<0.001). The nurse screening and intervention process was reported acceptable by 74% of patients at follow-up and a majority (71%) of staff. CONCLUSIONS Screening and brief intervention in a sexual health clinic for risky alcohol consumption is feasible, acceptable and effective in producing significant reductions in drinking as measured by AUDIT. Both intervention and control groups decreased consumption, suggesting that screening alone is sufficient to influence behaviour. Further study of brief intervention in this setting is appropriate.