From data provided by a national census of treatment for alcohol problems in 1996, this paper reports findings on differences between three countries of the UK (England, Northern Ireland and Scotland). Wales and the Channel Islands were not included in this analysis because of especially low response rates. Countries did not differ in the numbers of clients seen per day or the gender balance of clients. Mean age of clients was highest in Scotland (44 years) and lowest in Northern Ireland (39 years). A higher proportion of clients seen in Northern Ireland were friends or relatives of problem drinkers seeking help than in the other countries. English agencies reported much larger proportions of 'Irish' clients than those in Scotland. Northern Irish agencies showed the highest proportion of married clients and also the lowest proportion of those divorced, separated or widowed, the highest proportion of whom was found in Scotland. The country recording the highest proportion of clients in insecure accommodation was England. Northern Irish agencies had the highest proportion of clients in employment and the lowest proportion on sickness or invalidity benefits. The highest proportion of professional staff delivering treatment on census day was recorded in Northern Ireland. Clients in Northern Ireland were less likely to complain about physical health consequences of drinking and more likely to complain about psychological consequences. The highest proportion of clients simultaneously attending Alcoholics Anonymous (AA) meetings was found in Northern Ireland. Known drug use was higher in agencies in Northern Ireland than in England and Scotland. Clients seen by agencies in Northern Ireland appear to form a distinct group from those seen in Scotland and England. These current differences in treatment provision may become especially relevant if increased devolution leads to greater divergence in the nature of treatment provision in the countries of the UK.