Introduction: The gradual increase in the number of companies that offer 24-hour services impacts the growing demand and recruitment of individuals to deliver these services at night. Working at night causes changes in the body that are associated with stress, which manifests through physical and psychological symptoms and may trigger work-related diseases. Objective: The aim of this research was to identify the stress level of night workers of a company responsible for receiving, sending and delivering mail in Brazil. Materials and methods: Cross-sectional, quantitative, qualitative, exploratory and descriptive study. Participants included 31 subjects, 29 men and 2 women, with a mean age of 46 years. For data collection, anamnesis and the Stress Symptom Inventory for Adults were used. Results: Even though most workers are not diagnosed with significant stress episodes, a considerable portion attributed increased stress to the work environment. Only workers with different levels of stress experience interference while performing their jobs. Conclusion: Preventive measures, both in organizational and/or personal ambits, may be adequate strategies to promote the quality of life of workers.