A cooperative study has reviewed the prevalence of arterial hypertension (AH) among 40- to 59-year-old male residents of three cities (Moscow, Minsk and Kaunas) and the possibility of organizing a long-term outpatient treatment of newly-detected AH cases as well as the efficiency of the latter. Of 16,703 individuals screened, AH was detected in 27.9%. Evidence is obtained that preventive and therapeutic procedures for hypertensive patients are in need of an improvement. In a middle-aged population, moderate AH is prevalent (nearly 67.7%). Coronary risk factors, such as hyperlipoproteinemia and excessive body weight, were more frequent in AH patients, as compared to the general population, an argument in favor of the need for an improved combined approach to AM control in the population. Active combined treatment of the recognized cases over 5 years proved effective as it brought arterial blood pressure back to normal. Patient participation in the treatment and its contribution to treatment efficiency are reviewed.