Assessments of patient-reported outcomes and health-related quality of life in cancer clinical trials have been increasingly emphasized recently because patient and public involvement in cancer treatment development has been promoted by regulatory authorities and academic societies. To assess patient experiences during and after cancer treatment, there is interest in implementing patient-reported outcome and health-related quality of life assessments into cancer clinical trials. The Japan Clinical Oncology Group quality of life ad hoc committee previously created a version of the Quality of Life Assessment Policy in 2006. Recently, there has been increasing demand from Japan Clinical Oncology Group researchers to assess patient-reported outcome/health-related quality of life in clinical trials. Although guidelines are available regarding planning and reporting clinical trials that include patient-reported outcome/health-related quality of life as an endpoint, there are still issues regarding the lack of consensus on standardized methods for analysing and interpreting the results. Hence, it was considered necessary to reorganize the Japan Clinical Oncology Group patient-reported outcome/quality of life research committee and to revise the former patient-reported outcome/quality of life research policy to promote patient-reported outcome/health-related quality of life research in future Japan Clinical Oncology Group trials. The purpose of this Japan Clinical Oncology Group patient-reported outcome/quality of life research policy is to define patient-reported outcome/health-related quality of life research and provide guidelines for including patient-reported outcome/health-related quality of life as an endpoint in Japan Clinical Oncology Group trials.