Introduction: Many factors are involved in nurse burnout. The aim of the study was to investigate the factors of burnout in 2 groups of nurses, specifically among those working in psychiatric stationary or outpatient wards during the COVID-19 pandemic. Material nad methods: The study covered 140 nurses. To assess the impact of factors on professional burnout during the COVID-19 pandemic, an original questionnaire was used assessing sociodemographic conditions, the need of additional medical use, as well as emotional factors.Results: The differences between stationary and outpatient wards related to discomfort due to the need to use protective clothing (100% vs. 27.78%, p < 0.00001), and nuisance and disruptions in interpersonal communication related to the use of protective masks (100% vs. 44.44%, p < 0.00001). Nurses from stationary units were the only ones who showed fear of infection (62.30%), difficulties at work (84.43%), fear of being infected and/or family infection (73.77%), feeling tired and depressed (70.49%), increased need for relaxation and rest (81.15%), and insomnia (66.39%). Differences also occurred among those working on 24-hour duties and those working shorter on 12-hour duties. The former were more likely to complain about excess responsibilities (100% vs. 43.75%, p = 0.00001), pain (100% vs. 8.75%, p < 0.00001). Emotional factors such as fatigue, depression, the need for relaxation, and insomnia correlated with age, work experience, and education (p < 0.00001). Conclusions: A more common incidence of identified factors that may influence burnout was observed in nurses working in stationary psychiatric units and working on longer 24-hour duties. Older, more educated, and more experienced nurses were more likely to exhibit emotional symptoms that may contribute to burnout during the COVID-19 pandemic. Nurses with a greater number of risk factors should be candidates for preventive procedures consisting of their allocation, psychological training, and care for their working conditions and environment, including physical activity and relaxation.