A 43-year-old man with oligoblastic leukemia and t(3;8) variant translocation is reported. At first he was classified as refractory anemia with excess of blasts in transformation according to the FAB criteria for myelodysplastic syndrome. Remission was obtained after intensive chemotherapy. After 8 months, a relapse occurred as overt M2 AML. At presentation chromosome study of bone marrow cells using R- and G-bandings revealed 45,X, -Y,t(3;8)(q29;q22) in 35 of the 42 metaphases analyzed and 46,XY,t(3;8) in one metaphase in addition to normal karyotype in the other six metaphases. However, RT-PCR assay showed no AML1/ETO fusion transcript. At relapse, a karyotype of 46, XY,t(3;8), deletion(4)(p14), add(7)(q32) was observed in all abnormal cells indicating a clonal karyotypic evolution. We believed that this case should be diagnosed as an early form of M2 AML initially. It may be the first case of oligoblastic leukemia with t(3;8) variant translocation. Further study is needed to elucidate its molecular entity.