The patient was a 55-year-old man who had been on hemodialysis for 6 years for diabetic nephropathy. He was clinically diagnosed with pulmonary tuberculosis with extrapulmonary lesion after 3 years of chronic fever. His fever subsided immediately after the beginning of antituberculosis drug therapy and the antituberculosis drugs were discontinued 3 days after the initiation of the therapy. He experienced a sense of drunkenness when he received isoniazid, apparently not in association with any of the other antituberculosis drugs given. His blood trough concentration of isoniazid was nearly equal to the usual peak levels measured in patients with normal renal function. Isoniazid is often prescribed for patients with chronic renal failure without dose-reduction, because of its hepatic metabolism. But blood level of INH was found to accumulate at high levels in this patient. The high blood concentration of isoniazid in this patient with chronic renal failure may have elicited his neurological side effect.