We describe a 41-year old man with obsessive-compulsive neurosis who developed acute renal failure (ARF) due to acute interstitial nephritis (AIN) during 6 weeks of treatment with clomipramine hydrochloride (CPH). He had a slight fever, mild arthralgia, appetite loss, and diarrhea after taking CPH. On admission, he showed serum creatinine (sCr) of 7.31 mg/dl, and creatinine clearance (Ccr) of 2.5 ml/min. He subsequently became anuric and required hemodialysis. Renal biopsy revealed AIN with diffuse mononuclear cell infiltration. After the withdrawal of CPH and treatment with prednisolone (PSL) 0.5 mg/kg per day, his urinary output improved, along with improvement of his renal function; therefore hemodialysis was finally discontinued. To our knowledge, this is the first case report of AIN induced by clomipramine.