We examined the potential impact of negative peer influence within a treatment-focused residential care setting. Subjects were 712 youth consecutively admitted to a large residential treatment program (9–19 years of age). Based on Diagnostic Interview Schedule for Children (DISC) scores, 247 (35%) of these youth qualified for a Conduct Disorder diagnosis at admission. The dependent measures were the number of DISC Oppositional Defiant Disorder (ODD)/Conduct Disorder (CD) symptoms and the sum of Conduct Problem behaviors observed daily for each youth. Both the Conduct Problem Behaviors and the ODD/CD symptoms for both CD and non-CD groups decreased over time. Youth with a CD diagnosis or who were female improved at a faster rate than their peers. The data analyzed in this study do not support a negative peer influence effect for antisocial youth placed in a treatment-focused residential care setting.