Background. Co-operation between mental health care units and the social services is important in the case of people with social problems who also suffer from mental health problems. However, participation of patients and their families in the treatment process, and co-operation between them and the professionals, are also important. Communication between the professionals, patients and their family members, and the professionals is a crucial factor for co-operation. Aims and objectives. The aim of this study was to elucidate the experiences and importance ofco-operation for the patients. The data consisted of interviews with 22 mental health patients who were also clients of municipal social services. Method. The grounded theory approach was used, focusing on the informants' experiences of the integrated network and family-oriented modelfor co-operation. Results. The findings indicate the importance of the participation of patients and their social networks in psychiatric care or the treatment process. Meetings should be characterized by open and reflexive discussions with all participants' points of view being included, so that fruitful co-operation is possible. However, some negative experiences were also reported, all of which were connected with the professionals' behaviour. Conclusions. Trust and honesty are essential elements in relations between professionals and psychiatric patients, but it cannot be assumed that they will develop naturally. It is the professionals' responsibility to adjust their behaviour so that these elements can be created in a mutual process between patients and professionals. Multidisciplinary teams are a necessity in family-oriented co-operation between psychiatry and social services, and in a satisfactory caring process. Relevance to clinical practice. Nurses' work is often individually oriented and nurses are ruled by routines in their work. The mental health caring process should be seen as a shared process between the patient, his/her human environment and professionals for which nurses need skills to their interaction with patients and their social network.