The benefits of lowering a systolic blood pressure below 140 mmHg in elderly hypertension remain controversial. This study is a prospective, randomized, open-label study with blinded assessment of endpoints to compare the 2-year effect of strict treatment to maintain systolic blood pressure below 140 mmHg with that of mild treatment to maintain systolic blood pressure below 160 but at or above 140 mmHg in elderly hypertensive patients. Patients with essential hypertension (65-85 years old, with a pretreatment systolic blood pressure of above 160 mmHg) were randomly assigned to receive strict treatment (n=2,212) or mild treatment (n=2,206). The baseline drug was efonidipine hydrochloride, a long-acting calcium antagonist. The primary endpoint was the combined incidence of cardiovascular disease and renal failure, and the secondary endpoints were total deaths and any safety problems. Although final blood pressures (systolic/diastolic) were significantly lower in the strict-treatment group compared with the mild-treatment group (135.9/74.8 vs. 145.6/78.1 mmHg; p<0.001), the incidence of the primary endpoint was similar in the two groups (86 patients in each group; p=0.99). Total deaths were 54 in the strict-treatment group vs. 42 in the mild-treatment group (p=0.22), and treatment was withdrawn because of adverse events in 36 patients in each group (p=0.99). An interaction between age and treatment for the primary endpoints (p=0.03) was seen. Complex clinical features associated with aging seem to have obscured the difference in effect between the two treatments. Further studies are needed to assess the optimal treatment strategy for hypertension in the elderly.