This article examined the relation of five subtypes of trauma symptoms to hypothalamus-pituitary-adrenal (HPA) functioning as assessed with salivary cortisol before, during, and after an experimentally induced interpersonal conflict task in 194 heterosexual young adult couples. Trauma history and symptoms were assessed through structured clinical interviews and standardized self-report measures. Hierarchical linear modeling was used to analyze the effects of trauma symptoms on trajectories of cortisol reactivity to and recovery from the interpersonal stress. Trauma-related anxiety, depression, sleep disturbances, and dissociation significantly predicted cortisol reactivity and recovery. Trauma-related anxiety, sleep disturbances, and sexual problems significantly predicted partners' cortisol reactivity to interpersonal stress.