The present study used data from an ongoing longitudinal study of the effects of maltreatment on adolescent development to (1) describe rates of maltreatment experiences obtained from retrospective self-report versus case record review for adolescents with child welfare–documented maltreatment histories, (2) examine self-reported versus child welfare–identified maltreatment in relation to mental health and risk behavior outcomes by maltreatment type, and (3) examine the association between the number of different types of maltreatment and mental health and risk behavior outcomes. Maltreatment was coded from case records using the Maltreatment Case Record Abstraction Instrument (MCRAI) and participants were asked at mean age = 18.49 about childhood maltreatment experiences using the Comprehensive Trauma Interview (CTI). Results showed that an average of 48% of maltreatment found by the MCRAI for each type of maltreatment were unique cases not captured by the CTI, whereas an average of 40% self-reported maltreatment (CTI) was not indicated by the MCRAI. Analyses with outcomes showed generally, self-reported maltreatment, regardless of concordance with MCRAI, was related to the poorest outcomes. The difference in associations with the outcomes indicates both self-report and case record review data may have utility depending on the outcomes being assessed.