Aims — Monitoring of a community mental health service is presented, aimed at describing patients' demographic and clinical characteristics, pathways to care and decision—making process for the first contacts, distribution of interventions according to diagnoses, patterns of service utilization, and finally variables associated with intensity and duration of care, testing the hypothesis that high and long—term users are the most disadvantaged patients with regard to social and clinical variables. Design — Observational study, based upon first year implementation of the local informative system. Setting — Community Mental Health Service, San Giorgio di Piano, Bologna, Italy. Main outcome measures — The relative risk of being a high long—term user was computed for some socio—demographic and clinical variables against the reference category, i.e. the most favoured group. Confounding effects between social and clinical variables were controlled using stratified analysis. Results — Crude rates are presented for one—day prevalence (635.4/100.000 adult inhabitants) and one—year prevalence (1314.1/100.000). Among patients in contact with service at census day schizophrenic— type psychoses are prevailing, while patients coming for treatment in 1993 have more frequently organic psychoses and neurotic disorders. After the first contact 50% of patients are not taken in care; decision seems to be based on diagnosis and not connected with past psychiatric history or socio—demographic characteristics. Forty—nine per cent of outpatient care is delivered to 20% schizophrenic—type psychoses; moreover, this group of patients is seen to receive a wider range of interventions. Inpatient care is rare even for the most serious diagnoses; the global ratio between nonhospitalized and hospitalized users is 12.5 to 1. Factors significantly associated with long-term high user outcome are: being under 55 years old, unmarried status, living alone or without family, having functional psychosis, and having been long-term patient in 1992. Conclusions ‖ Consistently with the local guidelines for mental health care, service's resources are mainly devoted to most seriously ill patients. Evidence is shown for a strong community tenure and for a higher proportion of long-term users than in other Italian services. The hypothesis that high and long-term users are more disadvantaged is confirmed, even if no significant outcome difference is seen according to sex, educational level and occupational status.