Many complicated technical factors are involved in selecting a radiation oncology information management system. This report presents a discussion of some important information systems components and concepts which should be considered when evaluating vendor options. Network operating systems, database management systems, network infrastructure, and client issues are all presented. The current marketplace of products is analyzed from both a features and a systems standpoint. Because selection of an appropriate system is a highly site-specific matter taking into account many important factors, general recommendations are difficult. Nonetheless, current market leadership by certain vendors and a broad sense of the future direction are indicated in the conclusions.