In an attempt to improve physicians' laboratory practice behavior, the Department of Hospital Laboratories at the University of Massachusetts Medical Center developed a rotation for first year housestaff. Medical interns were chosen for this pilot program because they are the most frequent users of our laboratory facilities. Rotations provide an overview of the laboratory organization, quality control and assurance, appropriate use of laboratory testing, cost containment, and an introduction to different laboratory disciplines. As assessed by discussions during an interview following completion of the program, the participants have shown an increased understanding of how a modern hospital laboratory functions and of the complexity of services provided. The respect for the laboratory staff and confidence in test results issued have increased, and house officers are more likely to use laboratory services in a more cost-efficient manner.