BACKGROUND: For treatment of chronic musculoskeletal disorders pains to be successful, drug interventions are required. OBJECTIVE: In this study, we aimed to evaluate the Rational Drug Use Knowledge Level (RDUKL) in patients with musculoskeletal disorders and some relevant factors. METHOD: The study was carried out in October 2017 on patients treated in the Physical Therapy Rehabilitation Hospital in Turkey. The prepared questionnaire and RDUKL scale were administered to 239 patients by face-to-face interviews. The ANOVA test, chi -squared test and logistic regression model were used for the statistical evaluation. RESULTS: Forty-three percent of the study group was found to have Rational Drug Use Knowledge (RDUK). The patients who used medicines under family supervision had twice as much RDUK as those who did not use medicines under family supervision, and those who were university graduates had six times as much RDUK as those who had primary education or below. Scale score was found to be low in patients with fibromyalgia and high in patients with rheumatoid arthritis (p < 0.05). CONCLUSION: RDUKL was found to be low in the group with chronic diseases and high average age. Besides training, it is important to provide patients with family support about their illness and its treatment. Thus, positive contributions can be made to the increase of the RDUKL.