The five part study: 1. identified the incidence cohort and tested the hypotheses that over the 25 year study period the incidence of deep venous thrombosis/pulmonary embolism had decreased, the extent of testing for suspected deep venous thrombosis/pulmonary embolism had increased, and the number of tests obtained for patients with deep venous thrombosis/pulmonary embolism had increased. 2. determined the independent risk factors for deep venous thrombosis/pulmonary embolism and estimated the population attribute risk due to each independent risk factor for deep venous thrombosis/pulmonary embolism in a case-control study of the incidence cohort and community controls. 3. tested the hypothesis that deep venous thrombosis/pulmonary embolism were independent risk factors for death after adjusting for age, sex and co-morbid conditions. 4. described the occurrence of the post-phlebitic syndrome, pulmonary hypertension, and recurrent deep venous thrombosis/pulmonary embolism over the 25 year study period and identified the independent risk factors for lower extremity venous ulceration. 5. evaluated the accuracy of national pulmonary embolism mortality rates by comparing pulmonary embolism mortality rates calculated from a review of all the inpatient and outpatient medical records of Olmsted County deep venous thrombosis/pulmonary embolism patients with death certificate pulmonary embolism mortality rates for Olmsted County from the National Center for Health Statistics. The study provided the most complete and comprehensive population based estimates of the incidence, risk factors, survival and outcomes of deep venous thrombosis/pulmonary embolism available to date.