A 43-year-old woman with pulmonary alveolar proteinosis (PAP) was successfully treated with living-donor lobar lung transplantation (LDLLT). The patient's PAP had been diagnosed at age 35. She had been treated with repeated bronchoalveolar lavage and granulocyte-macrophage colony-stimulating factor (GM-CSF) inhalation therapy despite having no serum anti-GM-CSF autoantibodies. At age 42, her respiratory condition became critical and she underwent transplantation from two donors. While careful observation was needed for the recurrence of PAP in the transplanted lungs, she was functioning well without oxygen therapy 1 year after transplantation. This appears to be the first report of LDLLT for PAP in an adult.