Information systems (IS) success is one of the most widely used dependent variables in information systems research. Not surprisingly, much attention has been given to how best to measure it (e.g., DeLone and McLean 1992, 2002, 2003; Rai et al. 2002; Seddon 1997; Seddon et al. 1999). In this paper, we identify measures that can be applied to assess the success of open source software (OSS) projects based on a brief review of the literature, a consideration of the OSS development process and an analysis of the opinions of OSS developers. Since project success is likely to be a multidimensional construct, especially for OSS, our goal is to present a range of measures for future researchers to consider. As Seddon (1999) says, a “diversity of IS effectiveness measures is to be encouraged.”