Despite increased competitive pressures in the volunteering industry, the structure of competition within this non-profit sector has not been examined in the past. This study uses selected respondents from the 1999-2002 World Values Survey who have previously volunteered for multiple organisations. Based on the patterns of organisations that volunteers donated their time for, competition between volunteering organisations with different missions was analysed, resulting in five dimensions of volunteering missions within which volunteering organisations appear to be competing: altruistic, leisure, political, church, and other missions. The altruistic mission groups is the broadest and includes a wide variety of volunteering goals, whereas the church seems to stand without much competition, thus being confronted with the least competitive threat in the fight for volunteers. Such analyses would be useful for managers faced with the challenge of retaining current volunteers and recruiting new volunteers in an increasingly competitive volunteering marketplace. As such, the proposed approach represents a way of analysing the competitive market structure analysis in the volunteering market, thus providing volunteering organisations with a useful tool from the marketing toolbox.