We report a patient who received a single, left lung transplantation for idiopathic pulmonary fibrosis. The effect of the graft on pulmonary improvement was only temporary, because the patient developed obliterative bronchiolitis (OB), resulting in complete destruction of the graft. The patient, however, remains alive 6 years after OB was diagnosed, apparently as a consequence of native lung improvement with triple-immunosuppressive medicine. This case is of interest for several reasons: first, it shows that pulmonary fibrosis may respond to intensive immunosuppressive therapy; second, it demonstrates that ventilation scintigraphy is useful in addition to pulmonary function tests in estimating the actual function of the graft after single lung transplantation; and third, it appears that the gradation of bronchiolitis obliterans syndrome (BOS) after single lung transplantation may overestimate the true function of the transplant.