Participant turnover in open source software development is a critical problem. Using Schneider’s (1987) Attraction Selection and Attrition Framework and the notion of Person- Organization fit, we hypothesize about the relationship between a participant's fit with an open source project and turnover. Specifically we predict that value fit, needs-supplies fit and demandsabilities fit between a participant and a particular project will have a negative association with participant turnover and that the role of the participant in the project acts a moderator. An empirical study is designed to examine the hypotheses using a combination of survey and archival data. Since for-profit companies are increasingly leveraging open source software development, implications of our findings will be useful for project managers seeking to retain talented contributors in the absence of financial compensation.