e20699 Background: The most important issue, which may be preventing effective cancer pain management, have generally been the barriers originating from misbelieve or misunderstandings, which lead patients to be reluctant to report pain and receive the appropriate analgesic. It is the first study about this issue in Turkey. Methods: This study was planned as a descriptive and cross-sectional. The sample was 170 patients with cancer, who used or is still using analgesic medication for pain related to cancer. Demographic Questionnaire, Brief Pain Inventory and BQ-II were used for data collection. The reliability coefficient for the total scale and subscales (Cronbach's α) were calculated. Test and retest results were compared to determine the scales validity for Turkish patients. All statistical analyses were performed with the SPSS 15.0.The value p≤0.05 was considered ‘statistically significant’. Results: As a result of the factor analysis made for BQ-II, seven factors that make up for 66.451% of the total variance were found. Cronbach's alpha value was 0.87 for the BQ-II. According to the points given by patients to the items in BQ-II, it was seen that they have beliefs that may be barriers to optimal pain management mostly in “addiction” and minimally in “physical side effects” subscale. It was ascertained that male, not married patients, patients with a chronic disease other than cancer, patients whose “average pain” level is >5 and who use inadequate analgesic have more beliefs that may be barriers to optimal pain management. Conclusions: BQ-II was a valid and reliable scale for Turkish defining patient related barriers in cancer pain management. Items suggested by patients such as “family related barriers” and “family members’ role and responsibilities” could be added to the BQ-II for future studies. No significant financial relationships to disclose.