To assess and understand the level of job burnout among the medical librarians and identify the factors affecting it, email survey, consisting of questions regarding personal background, organization characteristics, degree of burnout, and coping activities, was administered for two weeks in December 2016, to the librarians in 138 institutions affiliated with the Korean Medical Library Association. MBI-GS is used as a burnout measuring instrument. Data collected from 158 librarians (response rate 65.6%), were analyzed by descriptive statistics, t-test, ANOVA, and correlation analysis methods. According to MB-GS norm, respondents experience moderate level of exhaustion and professional efficacy, however the level of cynicism is extremely high. There are significant statistical differences in burnout, depending on age, medical librarian certificate, work experience, type of library, job coverage, and coping activities. There are also statistical significant correlations between workload, role conflict, decision making process and performance evaluation, organization communication, IT environment, continuing education and burnout. Based on the results, recommendations to alleviate burnout are suggested in individual, organizational, and professional association context.