Community psychiatric teams are an integral part of modern mental health services. The development of such teams has allowed the care of patients to be transferred from institutions to the community. A Cochrane review of community-based programmes showed that community team-based psychiatric services led to a reduction in suicide rates, improved patient engagement and were more acceptable to patients (Tyreret al, 1999). Community care also reduces the number of days patients stay in hospital, but not the number of admissions (Marshallet al, 1995). However, community mental health teams (CMHTs) have been criticised for their ambiguous and overambitious aims, and their tendency to neglect people with the most challenging health- and social-care needs (Patmore & Weaver, 1991; Sayceet al, 1991). All mental health workers are not necessarily eager, or skilled, to work effectively in teams. Building and maintaining an effective team requires commitment, clarity of purpose, a shared vision and frequent review of team operations. In a previous issue ofAPT, Burns & Guest (1999) described the adaptation and running of an assertive community treatment team in an inner-city area. Here I examine the attributes of effective CMHTs (Box 1), enumerate barriers and challenges to team-working (Box 2) and suggest strategies for improving team effectiveness (Box 3).