Objectives: The aim of this study was to assess the validity and reliability of the Serbian versions of the Copenhagen Burnout Inventory (CBI) and the Study Burnout Inventory (SBI) among fifth-year medical students at 5 universities in Serbia. Material and Methods: The study included 573 fifthyear medical students at 5 universities in Serbia. The research instrument consisted of SBI and CBI. The reliability of these instruments was assessed using an internal consistency measure (Cronbach’s α), an intra-class coefficient (ICC) and factor analysis. Results: Cronbach’s α for SBI was 0.83, including for exhaustion 0.73, for cynicism 0.70, and for inadequacy 0.48. The test-retest reliability (ICC) was 0.75. Cronbach’s α for personal burnout on CBI was 0.89, for the faculty-related burnout 0.86, and for the faculty-members-related burnout 0.92. Cronbach’s α for CBI was 0.93. The factor analysis for SBI showed 2 factors and for CBI 3 factors. Conclusions: This study revealed that the Serbian versions of both SBI and CBI could be used for the assessment of burnout in this population. Int J Occup Med Environ Health. 2021;34(6):737–45