The present study provides preliminary evidence that pretreatment reward-related brain function in the striatum and medial prefrontal cortex (PFC) could have relevance for predicting both final level and rate of change of clinical characteristics in adolescents with major depressive disorder. Adolescents with depression underwent a functional MRI scan during a monetary reward task, participated in an 8-week open trial of cognitive behavioral therapy (CBT) or CBT plus selective serotonin reuptake inhibitor, and completed reports of anxiety and depressive symptoms before, during, and after treatment. Clinicians rated adolescents' improvement and severity at the same time points. Growth models were used to examine change in clinical characteristics and its association with brain function. Severity, anxiety symptoms, and depressive symptoms decreased over treatment. Final levels of severity and anxiety symptoms were associated with pretreatment striatal reactivity, and rate of anxiety symptom reduction was associated with greater striatal reactivity and lower medial PFC reactivity.