Stress in close relationships can have significant negative consequences for mental health, physical health, and long-term relationship functioning. Dysregulated physiological responses to stress are potential pathways through which relationship stress may lead to these kinds of outcomes, and the ways in which individuals attempt to cope with relationship stress are likely to impact their physiological responses. However, our understanding of the specific coping strategies that predict physiological reactivity and recovery in these contexts is rather limited. This study explored relations between young adult college students' self-reported methods of coping with stress in their romantic relationships and their physiological reactivity to and recovery from negotiating conflict with their romantic partners. Partners' coping styles were also examined as predictors of physiological stress responses. One hundred and ninety opposite-sex couples (N = 380; modal length of relationship = 1-2 years) participated in an experimental conflict discussion task. Physiological stress reactivity to the task was assessed using salivary cortisol, a primary hormonal product of the hypothalamic-pituitary-adrenocortical (hPa) axis. growth modeling of the cortisol levels before, during, and after the conflict task indicated that men who typically coped with relationship stress by seeking social support showed greater physiological reactivity to the conflict task. Partners' need for social support predicted stronger stress responses for both men and women, as well. while seeking social support is generally thought to be an adaptive coping strategy for couples, the results suggest that within the context of conflict negotiation in which receiving and providing support may be more difficult, seeking support from a partner is associated with greater phyisological stress.