Reams of data pertaining directly to the core health services research mission are accumulating in large-scale organizational and clinical information systems. Health services researchers who grasp the structure of information systems and databases and the function of software applications can use existing data more effectively, assist in establishing new databases, and develop new tools to survey populations and collect data. At the same time, informaticians are needed who can structure databases that serve the needs of health service research and who can design and evaluate applications that effectively improve health care delivery. As long as health services researchers and informaticians work in separate spheres, however, opportunities to use data from health care encounters to improve care, expand knowledge, and develop more effective policies will be missed. This paper provides a brief exploration of 1) existing successful collaborations between health services researchers and informaticians and 2) needs and opportunities for additional joint work in several core research areas.