This research uses interdependence theory to examine the link between commitment, costs, and willingness to sacrifice within interdependence dilemmas occurring in intimate relationships. Advancing prior work, which has demonstrated a positive association between relationship commitment and willingness to sacrifice, we investigated the moderating role of the cost of sacrifice in a scenario-based survey. Consistent with our hypotheses it was found that in high cost interdependence dilemmas, significantly greater levels of sacrifice were observed from individuals classified as high in commitment than from individuals classified as low in commitment. However in low cost dilemmas the relationship between commitment and sacrifice disappears. Possible differences in motivations for sacrifice are discussed with respect to this finding. Copyright © 2003 John Wiley & Sons, Ltd.