The purpose of this study was to evaluate the validity and reliability of the Barriers Questionnaire II (BQ-II) for Turkish patients and to define the patient-related barriers to cancer pain management in Turkey. For this, 170 patients with cancer who used or were still using analgesic medication for pain related to cancer participated in the study. It was found that patients have beliefs that may be barriers to optimal pain management, mostly in relation to addiction, and to a small extent, physical side effects. It was ascertained that male, unmarried patients, patients with cancer who also have another chronic disease, patients whose "average pain" intensity is more than 5 for the past 24 hours, and patients who use an inadequate analgesic have more beliefs that may be barriers to optimal pain management. It was concluded that the BQ-II is a valid and reliable scale in Turkey for defining patient-related barriers to cancer pain management.