Conduct problems in girls are relatively common, yet the study of Conduct Disorder and its comorbid conditions has been a highly neglected area of study. While significant advances have been made in the etiology, comorbidity, and prognosis of Conduct Disorder in boys, little to no advancement has been made in understanding the development of Conduct Disorder in girls. The goal of this study is to examine the development of Conduct Disorder in a large (N=2,484) community sample of inner-city, prepubertal girls (ages 6 to 8 at the beginning of the study), who are mostly African-American and Caucasian. There are three main aims of the proposed study. First, models that include a combination of behavioral, cognitive, and emotional factors as developmental precursors to Conduct Disorder in girls will be emotional factors as developmental precursors to Conduct Disorder in girls will be tested. Second, risk and protective factors that influence both the development of Conduct Disorder by affecting the precursors, and the continuity and severity of Conduct Disorder will be elucidated. Finally, comorbid conditions that affect the course of Conduct Disorder and development of comorbid Conduct Disorder and internalizing disorders will be identified. The proposed study will follow girls annually for a five-year period and will provide information that is critical to the understanding of the etiology, comorbidity, and prognosis of Conduct Disorder in girls.