Marathon running is a leisure behavior that has seen tremendous growth during the past decade. The purpose of this study was to gain a better understanding of factors associated with commitment to running for marathon participants. This study was designed to investigate the relationships among negotiation-efficacy, leisure involvement, and psychological commitment for individuals who had participated in a marathon event. A three-facet involvement measure was confirmed and then combined with negotiation-efficacy to predict commitment to running. The results revealed that two involvement dimensions and negotiation-efficacy explained 72% of the variance in commitment. A discussion of findings from the study as well as practical implications and suggestions for future research are presented.