Although Open Source Software (OSS) is popular, its continued use in organizations remains an issue, as evidenced by users reporting frequent problems, experiencing hold-ups, and running into implementation and integration issues. Often, it is argued that fit between the person’s task, values and work demands pose challenges for the successful use of OSS. In this context, this study draws on the concepts of task-technology fit and person-organization fit to develop a model to explore how different dimensions of fit interact with each other to influence OSS user’s productivity and innovation performance. Survey data was collected from OSS users to test the proposed model. Results of the analysis show that when there is fit between an individual’s OSS skills and the nature of the task to be performed (demand-ability fit), an OSS user’s productivity performance increases, whereas, his innovation performance decreases. Further, when the organization’s OSS values matches that of the individual user’s (value-based fit), his task productivity decreases. Implications of the results suggest that organizations that intend to use OSS for a long time need to recruit employees keeping in mind the nature of their OSS projects and the demands and priorities of the tasks performed in the organization.