The creation of inter-agency partnerships to deliver mental health services that meet the health and social care needs of service users is now a central strand of UK national policy and a considerable body of literature has developed around the concept of partnership. The date, however, the focus has been on partnerships between the specialist health and social services, or between these services and primary care. In the course of a study aimed at identifying the mental health training needs of a broader range of community agency staff, it became apparent that partnership working was problematic for the majority of agencies. Focus group discussions were carried out with staff from 21 agencies working across five practice contexts. On the basis of the data obtained we describe the extent of inter-agency working and the barriers to its development. The implications for meeting clients' mental health needs are then considered and means suggested for broadening inter-agency working to include a wider range of relevant agencies.