The efficacy of specialist versus general practitioner (GP) treatment of problem drinkers was assessed in a randomised controlled trial. 40 problem drinkers referred consecutively to a specialist alcohol clinic by their GP were, after assessment, randomly allocated to either GP or specialist clinic treatment groups. All subjects received initial advice and counselling in the clinic about their drinking. The specialist clinic group received continued care from the clinic including, if necessary, admission to hospital. Patients in the GP group were returned to the care of the GP who was contacted and supported by the specialist. After 6 months of follow-up, there were significant reductions in alcohol consumption and alcohol-related problems in both groups. No significant difference was found between the two groups with respect to the main outcome measures. No differential treatment effect was found with the more severely dependent drinkers. The findings show that after an initial detailed assessment and advice session, the treatment provided by GPs is at least as effective as that from a specialist clinic with respect to improvements in drinking behaviour and alcohol-related problems. After initial assessment and advice, specialist clinics should encourage GPs to become more involved in the subsequent care of problem drinkers. Such a practice should be based on the individual patient's needs and the adequacy of support offered to GPs.