To determine the effect of dibutyryl cyclic AMP (DBcAMP) on ischemic acute renal failure (IARF), that disorder was induced in male Wistar rats. After the animals were anesthetized with sodium pentobarbital (50 mg/kg, i.p.), the right kidney was removed and the left renal pedicle was clamped for 60 min. DBcAMP (5 mg/kg, i.p.) was given each 30 min before and after the renal pedicle clamping in half the dose each. Twenty-four hours after surgery, the levels of serum creatinine, BUN, serum potassium, and FENa% were significantly less elevated; and the total urine volume was significantly less decreased for 24 h in the group of IARF given DBcAMP than in the group of IARF alone. The elevation in Ca2+ content of the renal cortex was also significantly lower in the group of IARF given DBcAMP than in the group of IARF alone. These data indicate that DBcAMP can produce a beneficial effect on experimentally induced IARF. Since the intracellular accumulation of Ca2+ has been reported to be a potentially harmful factor in the development of IARF, it is suggested that the effect of DBcAMP on IARF can be in part due to an inhibition of the intracellular accumulation of Ca2+ in the kidney.