Due to the rapid advance of the pandemic caused by COVID-19, several countries perceived that human and material resources would be insufficient to meet the demand of infected patients. The aim of this study is to analyze the knowledge of health professionals working in the pandemic about the application of ethical criteria in decision-making in situations of resource scarcity. This is a cross-sectional, descriptive, and quantitative survey study, conducted from June to December 2020, with health professionals working in the COVID-19 pandemic in Brazil. We applied a questionnaire to assess the professionals’ knowledge about ethical criteria in decision-making in the allocation of scarce resources during the pandemic, containing 14 questions and possible score from 0 to 70, which was developed by researchers from documents and protocols validated by organizations from various countries, available in the first months of the pandemic, a sociodemographic characterization questionnaire and a self-assessment questionnaire regarding knowledge about bioethics. A total of 197 health professionals participated in the study, 37.6% of whom were nurses and 22.8% of whom were physicians, working in the Family Health Unit (28.4%) with a degree at the level of specialization (46.2%). Moreover, (9.5%) of nurses, (18.2%) of dental surgeons and (24.4%) of physicians reported that they have no prior knowledge about bioethics. Physicians and hospital workers scored higher on the knowledge assessment questionnaire. The mean score of the participants was 45.4 (SD = 7.2). Investments in training and professional education in the field of health focused on Bioethics are necessary, considering models and ethical theories that help professionals, managers and society to better position themselves in the face of pandemic contexts.