Hypertension is a known risk factor for cardiovascular disease, but few epidemiological studies have examined simultaneously the effect of baseline blood pressure on the development of stroke, acute myocardial infarction (AMI), and end-stage renal disease (ESRD). In 1983, a large, community-based mass screening covered about 14% of the adult population in Okinawa, Japan. The total number of people screened was 107, 192 (51, 122 men, 56, 070 women). We had access to two independent registries of end-organ damage: the Co-operative Study Group of Morbidity and Mortality of Cardiovascular Diseases in Okinawa (COSMO) registry for stroke and AMI, and the Okinawa Dialysis Study (OKIDS) registry for ESRD. The total number of people registered was 4, 756 with stroke, 1, 059 with AMI, and 641 with ESRD during the study period from April 1, 1988, to March 31, 1991. By using the name, sex, birth date, and ZIP code of registrants, we identified those registrants who were screened in 1983 and had developed stroke, AMI, or ESRD. Hypertension was defined as systolic blood pressure (SBP) of 140mmHg or higher or diastolic blood pressure (DBP) of 90mmHg or higher. Other readings were regarded as normotensive. The prevalence of hypertension was 35.8% (N=37, 299). The cumulative incidence of stroke, AMI, and ESRD was 154, 21, and 19 subjects among those with SBP_??_119mmHg, and 1933, 315, and 71 subjects among those with SBP_??_160mmHg. Similarly, the incidence of stroke, AMI, and ESRD was 234, 44, and 25 subjects among those with DBP_??_69mmHg and 1980, 381, and 364 subjects among those with DBP_??_110mmHg. Hypertension was prevalent in the adult population in Okinawa, Japan, and was a significant predictor of stroke, AMI, and ESRD. However, the effect of blood pressure on target organs differed and was more evident in those with stroke than in those with AMI and ESRD. (Hypertens Res 2000; 23: 143-149)