During an intervention period of 1 to 2 months, a project team supported general practitioners (GPs) and nurses in four primary health care centres in Sweden in introducing new routines for detection and treatment of problem drinkers. After the implementation of the new methods, the GPs reported increased involvement in early detection and intervention significantly more often than the nurses did. A majority in both groups reported perceived improvement in skills. There was a significant positive change of the attitudes concerning working with alcohol-related problems in the nurses reaching the same level as the GPs. In the nurses, attitudes and self-perceived intervention skills were improved, but to a lesser extent than their practice. The results indicate that future efforts concerning improvement of primary health care staff involvement in alcohol interventions should focus on training, supervision, and giving positive examples, rather than on changing an already positive attitude towards alcohol intervention. The potential role of nurses is still uncertain and not utilized sufficiently.