The irrational prescribing of drugs seems to be a general problem in medical practice, occasionally leading to serious consequences. In order to improve the drug prescribing performance of medical students, a compulsory context-learning pharmacotherapy module was implemented in 1998 in the medical curriculum of 2nd-4th-year medical students at theVU University Medical Center (VUmc), Amsterdam, The Netherlands. As part of this program, preclinical medical students are taught how to select, prescribe, and evaluate a drug regimen rationally. The aim of this study was to investigate the effect of this preclinical pharmacotherapy program on the quality of rational prescribing during the ensuing clinical clerkship of these students in internal medicine. The results of this study indicate that preclinical context-learning in pharmacotherapy leads to the use of more rational prescribing modalities by medical students during their ensuing clinical clerkship in internal medicine. This effect was obtained not only with respect to the clinical topics in which training had been given as part of the pharmacotherapy curriculum, but also for other disease situations that the students dealt with. This implies that students not only remember the specific information they have learned during the training, but are also able to apply the acquired skills in new situations (transfer effect).