A 32-year-old immunocompetent man developed fever and malaise that persisted for three years. As he had no health insurance, he never received any medical treatment. On admission, chest X-ray revealed multiple cavitary lesions and his sputnum yielded acid-fast bacilli, that were identified as Mycobacterium kansasii with multidrug resistance. Although his general status improved transiently by antituberculous agents, he died of respiratory insufficiency after four months. The prognosis of Mycobacterium kansasii pulmonary disease is reported to be relatively good among non-tuberculous mycobacteriosis, however, physicians must pay careful attention to cases of delayed start of therapy or multidrug resistance, or both.