Background: Emotional labor (EL) is a competence balancing work engagement (WE) and authenticity in relationships with the patients with a depletion of psychophysical and emotional recourses. The main purpose of the study was to examine the reciprocal relationships between EL, WE and the level of occupational burnout syndrome (OBS) in a group of Polish nurses. The article presents the results of a study aimed at verifying how hiding feelings (HF) and the deep acting of emotions (DA) in contacts with patients serve as moderators in the relationship between WE and the OBS level. Material and Methods: A cross-sectional study was conducted using the quantitative methodology with a correlation design. All the participants completed 3 standardized questionnaires (Polish versions): the Link Burnout Questionnaire, the Deep Acting and Surface Acting Scale, and the Utrecht Work Engagement Scale. The research sample was randomly selected in one of the hospitals in Kraków. Data saturation was completed upon obtaining a set of 100 correctly completed questionnaires. The study covered 100 nurses (age: M±SD = 36.91±10.12 years, seniority M±SD = 14.77±10.89 years). For the analysis of the data, the IMB SPSS Statistics 24 with Hayes PROCESS version 3.1 was employed. Results: The study has revealed that there is a negative relationship between WE and OSB, and a positive relationship between HF and OBS. The results have indicated that as the level of WE drops, the importance of HF for explaining the increase in OBS rises. If a low WE coincides with frequent HF, the risk of OBS increases. Conclusions: Work engagement is a construct distinct from, and negatively related to, burnout. A high level of identification and engagement in the work may protect people who hide their emotions from the risk of OSB. Emotional labor may lead to a variety of negative consequences, at the same time forming a personal resource of a medical worker. Med Pr. 2019;70(6):711–22