UNLABELLED: Although the impact of sleep deprivation on the development of psychological disorders is widely recognized, little is known about the longitudinal relationship between sleep quality and mood disorders, specifically among health professionals. OBJECTIVE: The objective of this study was to investigate the relationship between sleep quality and the incidence of mood disorders among health professionals who work night shifts, focusing on anxiety, depression, and stress. METHODS: This is an observational, cross-sectional, and quantitative study, approved by the Ethics Committee of the Christus University Center (Unichristus), in accordance with Resolution 466/12. It was carried out using an online questionnaire via Google Forms, in the city of Fortaleza, Ceará. RESULTS: A total of 45 health professionals from different areas took part in the survey, including nursing technicians, physiotherapists, nurses, and doctors. The results indicated a high incidence of sleep disorders, especially among nursing staff, with average scores of 11-13 on the Pittsburgh Sleep Quality Index (PSQI). The correlations found between sleep quality (as measured by the PSQI) and the symptoms of depression, anxiety, and stress were weak to moderate, with correlation coefficients (r) of 0.37, 0.44, and 0.48, respectively. CONCLUSION: The results suggest that there is an urgent need for interventions to improve sleep quality and reduce stress among health professionals working night shifts. Despite the promising findings, the study recommends further research to explore these relationships in more depth.