Three patients who suffered from congestive heart failure caused by severe hypertension were treated with a combination therapy consisting of angiotensin converting enzyme inhibitor (ACEI) and angiotensin II receptor blocker (ARB). Before initiation of treatment, all three patients showed elevations of serum creatinine concentration (sCr), plasma renin activity (PRA), and plasma aldosterone concentration (PAC), which indicated insufficient blood supply to the kidney during exacerbation of hypertension. All three cases successfully recovered from hypertensive heart failure with the combination therapy. sCr gradually decreased during continuation of the therapy, although one patient showed an increase in sCr at an early stage of the combination therapy. Blockade of the renin-angiotensin-aldosterone system (RAAS) by the combination of ACEI and ARB was well tolerated in patients with severe hypertension with renal damage and showed a beneficial effect in protecting against further renal damage. This result suggests that combination therapy with ACEI and ARB should be considered as a candidate treatment in cases of severe hypertension.