The goal of this study was to explore theoretically suggested but untested links between interparental conflict and stress physiology in late adolescence. A multi-method study was conducted involving families (n = 42) who previously participated in the University California, Irvine site of the NICHD Study of Early Child Care and Youth Development; adolescents were 17 1/2 years of age on average. Parent report and observer ratings of conflict, adolescent participation in a robust social-evaluative stressor, and assessment of cortisol, cardiovascular, and emotional functioning were included. Marital conflict was associated with dampened physiological stress responses in adolescence but sensitized emotional responses, suggesting that conflict may be associated with problems integrating and coordinating emotional and physiological responses to stress. (Contains 4 tables and 2 figures.)