Background: Postgraduate doctors are prone to burnout due to occupational and educational stressors. Sri Lankan situation is unknown. This study determines burnout among postgraduate doctors in Colombo: Prevalence, associated factors, and association with self-reported patient care. Methods: A cross-sectional study was conducted among 278 postgraduate doctors from eight specialties working in Colombo district, attached to the main postgraduate training institute for medical professionals. A selfadministered questionnaire was used. It comprised of the Copenhagen Burnout Inventory and an author-developed questionnaire, which was used to assess, associated factors and self-reported patient care. Prevalence of burnout was calculated. Associations were analysed using chi-square and binary logistic regression. Results: The response rate was 88.1% (n = 245). The prevalence of personal, work-related and client-related burnout was 41.6% (95% CI = 35.5-47.8%), 30.6% (95% CI = 24.8-36.4%), 8.9% (95% CI = 5.4-12.5%) respectively. Personal burnout was positively associated with, the trainee being a female, having a chronic disease, being involved in frequent unhealthy habits, having doctor parents, having homework demands and having emotional demands. It was negatively associated with, having frequent healthy habits, being satisfied with skill development opportunities, and frequent use of deep studying. Work-related burnout was positively associated with, female gender, being involved in frequent unhealthy habits, having homework demands and having emotional demands. It was negatively associated with, frequent use of deep methods of studying. Client-related burnout was positively associated with having emotional demands and negatively associated with being satisfied with training. The frequent self-reported, suboptimal patient-care practices: poor communication, poor clinical practice, poor response to patient's needs and poor communication during handing over were associated positively with clientrelated burnout. Conclusions: Most postgraduate doctors in Colombo have high personal and work-related burnout but clientrelated burnout is less. The factors associated with burnout need to be addressed by the programme managers of the postgraduate courses. Preventive measures should be introduced to reduce burnout among future postgraduate trainees of Colombo.