The purpose of this study was to investigate the relationships among selected demographic characteristics (income, education and age), motivation and commitment of volunteers at a sporting event. Three-hundred and five questionnaires were collected from volunteers in a marathon event and analyzed using structural equation modeling (SEM). Based on the results, the structural model illustrated that the paths of selected demographic characteristics, volunteer motivation, and volunteer commitment were statistically significant. The results of this study will contribute not only to an extension of the knowledge base of sport volunteerism, but also to practical applications for volunteer coordinators and event marketers.