A representative samples of 484 185 subjects 30-59 years were examined within the Cardiovascular Program of the Slovak Republic in the years 1978-1989. The results of the study concerning the occurrence and trends of selected cardiovascular diseases and their risk factors are presented in the paper. Within the given age range 20% of the population were found to suffer from one or more cardiovascular diseases. In the selected cardiovascular diseases the following prevalence was found: arterial hypertension in 10.7%, myocardial infarction in 0.6%, angina pectoris in 0.9%. The selected risk factors exhibited the following prevalence: diabetes mellitus in 4.0%, obesity in 32.3%, smoking in 28.3%, and hypercholesterolemia in 17.6%. Information on the occurrence and trends of cardiovascular diseases as well as on their interrelationship with risk factors is and essential prerequisite for efficient primary and secondary prevention. (Tab.10,Fig.13,Ref.33).