A 10-day-old boy treated in the intensive care unit and operating room due to hyperkalemia and renal failure. After admission to the intensive care unit and treatment for hyperkalemia, the patient required insertion of dialysis catheter in the operating room. Treatment for hyperkalemia continued while the patient was under general anesthesia. The operation was carried out successfully and cardiac signs and symptoms of hyperkalemia did not occur despite of potassium blood levels of 8.1 mEq x l(-1). General anesthesia could be safe in hyperkalemic patients as long as the treatment for hyperkalemia is initiated before and during the surgery and hyperkalemia inducing agents are avoided.