In the nationwide Community Hypertension Evaluation Clinic screening of more than 1 million people, the group classifying itself as overweight had prevalence rates of hypertension 50% to 300% higher than other screenees. Frequency of hypertension in overweight persons aged 20 to 39 years was double that of normal weight and triple that of underweight persons. Among those aged 40 to 64 years, the overweight group had a 50% higher hypertension prevalence rate than the normal-weight group and 100% higher than the underweight group. With each higher degree of blood pressure elevation, relative frequency of hypertension with overweight was larger. Thus this study confirms, in the largest group surveyed to date, similar findings in previous cross-sectional surveys. It is also consistent with data from longitudinal and intervention studies on the importance of overweight in relation to hypertension.