Objective: Cardiovascular reactivity to laboratory stressors was investigated as (a) a moderator of associations of partner aggression with affective functioning, alcohol problems, and parenting; and (b) a consequence of partner aggression. Method: Cohabiting adult couples (N = 453) with 3- to 7-year-old children were recruited by random digit dialing and completed questionnaires assessing couple physical aggression, discipline practices, anger, stress, depressive symptoms, and problem alcohol use. Heart rate and blood pressure were measured at rest and in response to laboratory stressors (mental arithmetic and video presentations of family conflict). Results: Males' physical aggression more strongly predicted women's affective functioning and alcohol problems when the women had greater cardiovascular reactivity. This pattern did not extend to men. Physical victimization was associated with lower cardiovascular reactivity. Conclusions: The present results provide partial support for the biological sensitivity to context model of Boyce and Ellis (2005) and suggest that incorporating the moderating influence of biological reactivity may improve the precision of models of the effects of aggression on adult adjustment. (Contains 5 tables and 1 figure.)