Objective: To assess the risk and predictors of service disengagement in adolescents with first-episode psychosis (FEP) receiving their first treatment in a long-standing early intervention and prevention center. Method: The Early Psychosis Prevention and Intervention Centre (EPPIC) in Australia admitted 157 adolescents, ages 15 to 18, with FEP from January 1998 to December 2000. Treatment at EPPIC spans an average of 18 months. Data were collected from patients' charts using a standardized questionnaire; 134 charts were available. Time to service disengagement was the outcome of interest. Baseline and treatment predictors of service disengagement were examined via Cox proportional hazards model. Results: Kaplan-Meier 18-month risk of service disengagement was 0.28. A lower severity of illness at baseline (hazard ratio [HR] = 0.2; 95% confidence interval [CI] 0.1 - 0.4), living without family during treatment (HR = 4.8; 95% CI 2.1 - 11.2), and persistent substance use during treatment (HR = 2.6; 95% CI 1.1 - 5.9) contributed significantly to predicting service disengagement. Neither initial substance use nor insight at baseline was related to service disengagement. Conclusions: Clinicians should focus on treating substance use and establishing a social network if family support is missing for adolescents with FER In addition, clinicians should apply strategies to keep in touch with those adolescents who may not see the necessity of continuous treatment because of a moderate severity of illness