Background. Analysing costs measures in conjunction with psychiatric case register (PCR) data can provide important epidemiologically-based information on resource utilization. Costing the service use patterns of first-ever patients can indicate the shape and likely resource consequences for mental health services operating within a community-based system of care. Methods. Yearly costs were calculated for the 299 first-ever patients and 768 longer-term patients who contacted the South-Verona Psychiatric Case Register between 1 January 1992 and 31 December 1993. Bivariate and multivariate analyses were used to compare costs between these groups and to test the associations between costs and the sociodemographic and diagnostic data recorded on the PCR. Results. For all diagnostic groups identified, first-ever patients were found to be less costly to support than longer-term patients, even after adjustment for various factors, including whether patients were single consulters. When multivariate analyses were employed, between 20% and 69% of the cost variation for first-ever patients could be explained by patient and other characteristics, and the effect of the contact (first or subsequent) variable was reduced. Conclusion. This study considered only the costs to the specialist psychiatric services but the methodology allows the likely annual resource implications of supporting new patients to be predicted from data collected at first contact. Such information can help ensure that services are adequately funded and that the resources are deployed appropriately between client groups.