Objectives: This study aimed (1) to determine the psychometric properties of a Thai version of the Maslach Burnout Inventory-Human Services Survey for Medical Personnel (MBI-HSS [MP]) and (2) to examine the mean scores of burnout and associated factors during the COVID-19 pandemic.Methods: Forward and back translations of the MBI-HSS (MP) questionnaire were performed. The Thai version was subsequently completed by 682 Thai physicians and nurses who worked during the COVID-19 pandemic. Exploratory factor analysis was performed on the first subsample (n = 341) by conducting Kaiser Mayer-Olkin sampling adequacy measurement and Bartlett's test of sphericity whereas confirmatory factor analysis (CFA) was performed on the second subsample (n = 341) using fit indices of the normed chi-square (chi(2)/df), the comparative fit index, the Tucker-Lewis index, and the root mean square error of approximation. This version's internal consistency was investigated using Cronbach's alpha coefficient. Demographic profiles were evaluated with descriptive and analytical statistics.Results: The Thai version of the MBI-HSS (MP) displayed good psychometric characteristics, as the Cronbach's alpha values of the 3 burnout factors ranged from 0.843 to 0.945. The CFA also showed good fit indices (chi(2)/df = 4.473; P < 0.001; RMSEA = 0.075 (95%CI = 0.055-0.079); CFI = 0.946; and TLI = 0.936). The physicians' mean EE, DP, and PA scores were 25.28 +/- 13.27, 7.15 +/- 6.11, and 36.83 +/- 8.13, respectively, whereas The nurses' mean EE, DP, and PA scores were 23.10 +/- 14.14, 4.43 +/- 5.06, and 35.67 +/- 10.24, respectively. Healthcare professionals who were younger, single, had fewer years of practice, and had more working hours per week tended to express more burnout scores.Conclusions: The Thai version of the MBI-HSS (MP) demonstrates good psychometric properties in assessing burnout among healthcare professionals. Several factors may be pivotal in intensifying burnout.