This paper explores the relationship between ego development and psychiatrically relevant behaviors in a group of hospitalized adolescents. Building on Loevinger's model of ego development, we administered the Sentence Completion Test to 114 adolescent girls and boys. To study psychiatric symptoms, Achenbach and Edelbrock's Child Behavior Checklist was used. With these procedures, the Achenbach and Edelbrock factor scores were compared to ego stage using correlational and multiple regression analyses. Findings indicate significant negative correlations with the externalizing and internalizing factors as well as a variety of behavioral subscales. A significant relationship also exists between the total number of symptoms and ego development. Ego development is found to be an important predictor for the externalizing factor and 2 subscales after the background variables of age, sex, and SES are partialed out. Our discussion addresses the question of the relationship between stages and transitions in ego development in relation to psychopathology. In addition, "age-stage dysynchronies" are discussed as ways of understanding psychopathology from a developmental perspective.