The three-dimensional (3D) virtual world is one of the current innovations that has been discussed extensively as the potential medium for online distance education. Despite the heated discussion on the possible applications of 3D virtual worlds for distance education, empirical studies were hard to locate, and little has been written about how these studies were conducted and what was found in general. The purpose of this content analysis was to investigate studies on integrating 3D virtual worlds into distance education and how these studies were conducted.