Burnout syndrome (BS) is characterized by high emotional exhaustion, high depersonalization and low professional accomplishment. OBJECTIVE: To determine the prevalence of BS in medical residents and to assess its relationship with work hours, medical specialty, year of residency program, gender, age and marital status. METHODS: An observational study was conducted in Recife, Brazil, from June to August 2008. BS was assessed using the Maslach Burnout Inventory. RESULTS: BS was diagnosed in 31.6% of the medical residents. No statistically significant association between the variables studied and BS was found. High emotional exhaustion was found in 67.1%, high depersonalization in 69.6% and low professional accomplishment in 43% of the medical residents assessed. CONCLUSION: The prevalence of BS in the medical residents was consistent with rates reported in the literature, although none of the risk factors assessed were significantly associated with the syndrome.