OBJECTIVE: To identify the treated incidence of psychosis in catchment of the Early Psychosis Prevention and Intervention Centre (EPPIC), Melbourne, Australia. METHOD: Cases were aged 15-29 years with a first episode of a psychotic disorder accepted into EPPIC between 1997 and 2000. Age- and sex-specific incidence rates per 10,000 person-years were calculated in 5 year age bands. Rate ratios were used for age group comparisons. RESULTS: The age-specific treated incidence of first-episode psychosis in 15-29-year old individuals was 16.7 per 10,000 person-years in males, and 8.1 per 10,000 person-years in females. The incidence was highest in 20-24-year-old males and in 15-19-year-old females. For both sexes, incidence rates were significantly lower in the 25-29-year age group. CONCLUSIONS: The incidence of psychosis in the catchment of EPPIC was higher than previously reported, especially in female teenagers. Peak rates in 15-24 year olds suggest a youth model approach to early psychosis may be indicated.