Several dietary factors have been shown to lower blood pressure in elderly patients in clinical trials, but it is not known how eating habits affect blood pressure control in outpatients treated with antihypertensive drugs. We obtained data on dietary information regarding food groups rich in potassium, magnesium, and calcium by submitting a questionnaire to 190 elderly outpatients. Blood pressure levels and the intensity and cost of antihypertensive treatment were obtained from clinical records. The mean age and blood pressure were 72.3±9.3 years and 138.7±15.2/74.6±8.8mmHg, respectively. Patients were divided into three groups on the basis of the intensity of medication: the LS group (n=52), treated with a low dose of a single drug; the HS group (n=95), treated with a high dose of a single drug; and the M group (n=43), treated with multiple drugs. Average age, body mass index, blood pressure levels, and extent of target organ damage were similar among the three groups. Intake frequency (rarely, once or twice per week, 3 to 6times per week, or every day) of the food groups was compared among the three groups. The LS group ate fruit (p<0.05) and seaweed (p<0.01) with significant frequency compared with the other groups, whereas milk and dairy products were taken with similar frequency by all groups. The monthly cost of antihypertensive medications averaged ¥17, 218±620 in the LS group, ¥17, 746±375 in the HS group, and ¥20, 066±1, 364 in the M group. These data suggest that habitual intake of foods rich in potassium and magnesium are associated with reduced intensity and cost of medication and with preservation of blood pressure control in elderly hypertensive outpatients. (Hypertens Res 2000; 23:195-200)