Burnout is common in many countries and is associated with several other problems, such as depression, anxiety, insomnia and memory deficits, and prospectively it predicts long-term sick-leave, cardiovascular disease and death. Clinical burnout or its residual symptoms often last several years and a common assumption is that recovery takes a long time by nature despite full time sick-leave and absence of work stress. Literature suggests models that hypothetically explain the development, but not maintenance, of the syndrome. Based on cognitive and behavioral principles and stress theory this paper describes a theoretical model explaining how clinical burnout can develop and be maintained. While the development of clinical burnout is mainly explained by prolonged stress reactions and disturbed recovery processes due to work related stressors, maintenance of the syndrome is particularly explained by prolonged stress reactions and disturbed recovery processes due to the new context of experiencing burnout and being on sick-leave. Worry about acquired memory deficits, passivity and excessive sleep, shame, fear of stress reactions, and the perception of not being safe are examples of responses that can contribute to the maintenance. The model has important implications for research and how to intervene clinical burnout.