The mortality with respect to the total population of Finnish physicians during the period 1953 to 1972 has been analysed and compared with the corresponding statistics for the general Finnish population, for Finnish foundry workers, and for American physicians. It was found that the overall mortality was lower for male physicians than that for the general population or for foundry workers, but was clearly higher than that for American physicians. Male physicians did not exhibit any major differences from the general population with regard to cardiovascular diseases and suicide, but had a lower mortality from malignant neoplasms, accidents and "other diseases" (including infectious diseases). The explanation of cancer mortality being lower than expected among male physicians was mainly to be found in a deficit in lung cancer. Although female physicians had higher life expectancy than male physicians and the female general Finnish population, they did not show any clear deficit for cancer. In respect of all specialists, surgical specialists had the lowest mortality; general practitioners had the highest mortality. Most of these variations were attributable to differences in coronary mortality, but mortality from lung cancer was also remarkably low among surgeons. Differences of a similar type were also found between occupational sub-categories; private practitioners had the highest, and research workers and central hospital physicians the lowest mortality figures. The lower cancer mortality among male physicians, as contrasted with the general population, is probably attributable to differences in smoking habits; about 22% of male physicians smoked in 1973, whereas earlier studies by others have indicated that the corresponding proportion was about 50% in the general population. In contrast, the differences in mortality between different specialist categories probably arises from other factors, since Finnish physicians reportedly display a relatively homogeneous smoking pattern.