All the male employees of the Italian Railroad system at work on April 1st 1963 have been classified by age, occupation, level of physical activity and other relevant social and working characteristics. Such cohort for a total of over 172,000 men has been followed for 5 years for all retirements and deaths. Five year analysis concerned relationship of physical activity to deaths has shown that overall death rates and specific rates for other degenerative heart disease, (excluding true coronary), chronic bronchitis and violence are higher in men engaged in heavy jobs as compared to others. No substantial differences were shown between occupations for cancer and strokes mortality. On the other hand death rates for myocardial infarction and sudden coronary deaths definitely prevail in sedentary and moderate workers as compared to heavy ones. The present project is concerned with the continuation up to ten years of the collection and analysis of deaths in such cohorts in order to provide a better picture of the overall relationship of habitual physical activity at work and other more or less related social and working characteristics to the subsequent mortality. Plans are being made to compare such 10 years data with other similar collected by Dr. Henry Taylor of the University of Minnesota, in a sample of American Rail Road Employees.