Objective: to identify biopsychosocial factors at work associated with the Burnout Syndrome in mental health professionals. Method: a cross-sectional study with a quantitative approach conducted with a sample of 293 mental health service workers from the public network of a municipality in the inland of the state of São Paulo, Brazil. An instrument composed of three self-administered questionnaires was applied, namely: biosocial data form, the Job Stress Scale (JSS) and the Maslach Burnout Inventory (MBI- HSS). The data were analyzed through the application of the Chi-squared and logistic regression tests, with the adoption of a 5% significance level. Results: Burnout Syndrome prevalence was 7% with a predominance of nursing professionals and was associated with the work sector, the use of psychotropic drugs, low satisfaction with the manager and with the low control over the work activity. Among the professionals with Burnout Syndrome, twelve performed functions considered of high wear, six performed passive work and two were in low wear activity. Conclusion: low control was the main psychosocial factor at work associated with Burnout Syndrome, making it necessary to develop actions that promote worker autonomy and improve the management of stress-triggering psychosocial factors.