As members of a human service profession, occupational therapists experience substantial amounts of stress. A number of studies have looked into the levels and sources of stress among occupational therapists. However, no study has examined how belief systems are related to occupational therapists' experiences of job-related stress. This study thus attempted to explore new ground by investigating the relationship between intensity of irrational beliefs and levels of stress. It also sought to examine associations between types of irrational belief and different sources of stress. A cross-sectional survey was carried out, during which self-report questionnaires were either posted or electronically mailed to practising occupational therapists in Singapore. Thirty-seven (53%) occupational therapists responded. The results showed that the intensity of irrational beliefs was unrelated to stress levels among the occupational therapists. However, certain types of irrational belief were related to the experience of certain sources of stress. In particular, low frustration tolerance was associated with stress regarding patient contact and irrationality in self-worth was associated with stress pertaining to rewards and recognition as well as to professional value. The possible explanations for such findings are explored in this paper. At the same time, the implications for practice are outlined, notably the proposal for cognitive strategies to be included in stress management programmes.