The purpose of this study was to explore issues arising from the promotion of collaboration between general practitioners (GPs) and community pharmacists in the management of leftover medicine. The 2016 Revision of Medical Fee newly added the check boxes in the prescription form in which a physician requests the correspondence of a pharmacy when confirming leftover medicine. In this study, we conducted a questionnaire survey among GPs in three wards of Tokyo in the month of November 2016. Of the 1,256 clinics queried, 283 responded to the survey. Among those GPs responding, 86.6% were concerned about leftover medicine of their patients, while 29.3% used the check boxes. GPs who received an explanation about the change of the prescription form demonstrated a significant increase in the use of the check boxes, compared to GPs who did not (p<0.01). Of the GPs surveyed, 71.0% thought that the check boxes were an advantage in recognizing medicines that the patients did not take. An overall 67.5% of the GPs who used the check boxes revised prescriptions based on the information from pharmacists. The study suggests that by increasing collaboration between GPs and pharmacists, the information from pharmacists could be utilized to revise prescriptions and lead optimization of drug treatment.