BackgroundSeveral studies have shown considerable differences in the way that physicians prescribe sick leave. The aim of this study was to examine the sick leave prescribing practices of occupational health care physicians and factors affecting these practices.MethodsA questionnaire study with 19 hypothetical patient cases was conducted among 356 Finnish occupational health care physicians. The effects of both physician-related and local structural background variables on sick leave prescribing were studied using regression models. Economic consequences of the variation in sick leave prescribing were estimated.ResultsWhen the cases were considered individually, the variation in prescribed sick leave days was relatively small. However, when considered together, variation in prescribing practice became apparent. On average, the overall number of days of sick leave prescribed for the entire group of 19 patient cases was 85.8, varying between 21 and 170 days. The physicians working at a public health center and those with more than 20 years experience as an occupational health physician tended to prescribe more days of sick leave than others. The quartile of physicians who prescribed the fewest days of sick leave would have resulted in mean production losses (17,100 euro, 95% CI 16,400-17,700) that were half those in the quartile with the most days of sick leave (34,800 euro, 95% CI 33,600-35,900).ConclusionsThere was variation in the sick leave prescribing practices of occupational health care physicians. The most significant factor affecting this variation was the health care sector (public, private or employer clinic) employing the physicians. Variation in sick leave prescribing patterns can lead to inequality between patients.