Objective: The aim of this study was to examine the differential effects of multi-types of maltreatment in an adolescent sample. Different combinations of maltreatment (emotional, sexual, physical, neglect) were examined in relation to both negative affect and externalizing symptoms in male and female youth. Method: One thousand four hundred fifty-two middle and high school youth were recruited from urban schools and a mandated early warning truancy program. Youth completed an anonymous survey that included measures of child maltreatment, depression, suicide proneness, hopelessness, delinquency, hostility, substance use, and promiscuity. Respondents were categorized into groups of different combinations of maltreatment by their reports of sexual abuse, physical abuse, neglect (emotional and physical), and emotional abuse. Results: Nearly two-thirds of boys and girls reported some form of maltreatment, and multi-type maltreatment was common (e.g., 13% reported experiencing both physical and sexual abuse and neglect). Individuals with maltreatment histories were more depressed (F=52.78, p less than 0.0001), suicide prone (F=24.29, p less than 0.001), and hopeless (F=32.07, p less than 0.0001) than non-abused individuals. Maltreated adolescents were also more hostile (F=35.03, p less than 0.0001), and they engaged in more delinquent behavior (F=26.76, p less than 0.0001), promiscuity (F=8.54, p less than 0.0001), and drug and alcohol use (F=9.61, p less than 0.0001). Individuals experiencing multi-type maltreatment were the most symptomatic, particularly youth with histories of physical abuse, sexual abuse, and neglect. In general, gender differences in effects were not observed. Conclusions: The results highlight the importance of studying combined types of maltreatment, as well as understanding the particularly deleterious effects of neglect and emotional abuse. The results are generally consistent with an additive model of maltreatment effects.