Introduction: Burnout is a state of mental and physical exhaustion which is developed under high levels of work-related stress. Burnout during residency training has gained significant attention since it leaves negative impacts on job performance and patient care. This study aimed at investigating the rate of burnout among residents in different medical fields. Method:A descriptive cross sectional study was carried out in 170 medical residents in Mazandaran University of Medical Sciences, 2012. Data was collected using a demographic questionnaire and Maslach Burnout Inventory (MBI).Results: Overall 52% of residents met burnout criteria ranging from 33% to 73% in different fields. There was a significant difference between specialties regarding emotional exhaustion subscale. (p=0.022). There was also a significant relationship between age and emotional exhaustion, in fact younger residents reported higher emotional exhaustion. (p=0.004) Conclusions:There was a considerable degree of burnout among residents and we found a relationship between educational field and emotional exhaustion. The highest degree of burnout was observed in Gynecology residents, and highest degree of emotional exhaustion was reported between younger residents.