Pharmacy school students were trained in a program simulating medication administration and giving adherence instructions. Following the training, the educational effects were evaluated. Students were separated into two groups. One group of students played the role of pharmacists and instructed simulated patients on medication adherence. Another group of students played the role of patients receiving simulated drug therapy; they were instructed on medication adherence by the students playing the role of pharmacists. The educational effects were evaluated using a questionnaire. The scores for "recognition of factors that influence medication adherence" tended to increase after the simulation, and they increased significantly after practical training. The scores for "self-evaluation of technique for instructing patients on medication adherence" increased significantly after the simulation, and they increased even more after practical training. The students' understanding of the effects on patients who were being instructed also increased significantly after the simulation, and these changes were maintained after practical training. In particular, students became more aware of the influence of pharmacists' attitudes. In practical training, the simulation training was helpful for bedside practice at hospital pharmacies and over-the-counter service at community pharmacies. Thus, the use of role play and simulated patients was an effective method for training pharmacy students to instruct patients on medication adherence.