Irritable urological symptoms with gross hematuria and bilateral lumbar pain developed when the patient received penicillin G for endocarditis. These symptoms were followed by renal insufficiency. A contrast-enhanced abdominal computed tomography (CT) scan revealed a thickened bladder wall, bilateral hydroureter and hydronephrosis, suggesting hemorrhagic cystitis complicated with urinary tract obstruction. Urine culture was negative. After discontinuation of penicillin G, all symptoms subsided and renal function recovered; hence, penicillin G seems to have been associated with hemorrhagic cystitis and acute kidney injury. Positive findings in the drug lymphocyte stimulation test (DLST) for penicillin G were consistent with this diagnosis.