This article reports on a study to uncover the health concerns of clients attending a methadone maintenance programme provided by an addiction service in Ireland. The Health Concerns Questionnaire 3 was completed by 261 clients attending methadone maintenance clinics. The most endorsed items tended to be psychosocial health concerns, particularly mood-related items. Additional comments highlighted various health issues including hepatitis C, diet, and sexual and mental health. Clients on methadone maintenance demonstrated a high level of health-related concerns. In particular, they were most concerned about mood and hepatitis C; these topics therefore merit attention from staff in addiction services. (C)2008 Nursing Times