Abstract We describe the case of a 64-year-old Japanese man with pancytopenia. Bone marrow biopsy findings were consistent with aplastic anemia. The patient was treated by transfusions without immunosuppressive therapy. Chromosome analysis of bone marrow cells at 6 months after onset showed a 46,XY,del(13) (q14q22) karyotype. The pancytopenia resolved gradually over the next 5 years; chromosome analysis of bone marrow cells at that time yielded normal findings. To our knowledge, this is the first report of spontaneous hematologic and cytogenetic remission of aplastic anemia. These findings suggest that the abnormal clone with deletion of the long arm of chromosome 13 was not sufficient for clonal evolution in aplastic anemia in this case1.