Knowledge transfer among geographically separated members is recognized as a critical ingredient for collaborative accomplishment of knowledge work in virtual teams. However, due to the "localness" of knowledge, such transfer of knowledge is believed to be inherently problematic, and thus, it is important to develop a solid understanding of the factors that enable knowledge transfer in such contexts. Drawing on existing literature on knowledge management and virtual teamwork, we identify 4 Cs (communication, capability, credibility, and culture) associated with individuals who are found to transfer significant amounts of knowledge to remote members, and test the 4 Cs in the context of US-Norwegian virtual teams engaged in systems development. A number of implications and directions for future research are also suggested.