AIM: This paper reports a study examining factors that may contribute to burnout among healthcare personnel. BACKGROUND: The impact on burnout of factors such as workload and interpersonal conflicts is well-documented. However, although health care is a moral endeavour, little is known about the impact of moral strain. Interviews reveal that healthcare personnel experience a troubled conscience when they feel that they cannot provide the good care that they wish - and believe it is their duty - to give. METHODS: In this cross-sectional study, conducted in 2003, a sample of 423 healthcare personnel in Sweden completed a battery of questionnaires comprising the Maslach Burnout Inventory, Perception of Conscience Questionnaire, Stress of Conscience Questionnaire, Social Interactions Scale, Resilience Scale and a personal/work demographic form. RESULTS: Regression analysis resulted in a model that explained approximately 59% of the total variation in emotional exhaustion. Factors associated with emotional exhaustion were 'having to deaden one's conscience', and 'stress of conscience' from lacking the time to provide the care needed, work being so demanding that it influences one's home life, and not being able to live up to others' expectations. Several additional variables were associated with emotional exhaustion. Factors contributing to depersonalization were 'having to deaden one's conscience', 'stress of conscience' from not being able to live up to others' expectations and from having to lower one's aspirations to provide good care, deficient social support from co-workers, and being a physician; however, the percentage of variation explained was smaller (30%). CONCLUSION: Being attentive to our own and others' feelings of troubled conscience is important in preventing burnout in health care, and staff need opportunities to reflect on their troubled conscience. Further research is needed into how a troubled conscience can be eased, particularly focusing on the working environment.