A fifty five-year-old male presenting as FAB M6 had blasts that were positive both for erythroblastic and megakaryocytic surface makers, i.e., carbonic anhydrase I, CD36 and CD41. HLA-DR and cD71 were also positive. In a very small portion, CD33 and glycophorin A were also positive. By Giemsa staining, these blasts were relatively large and had basophilic cytoplasm. By electroscopic study, PPO was negative and showed ferritin particles, theta granules and iron containing mitochondria in cytoplasm. Chromosome analysis revealed major karyotypic abnormality (MAKA). After initial treatment with blood transfusion, prednisolone and exymetholone, CD41b increased in positive ratio. Trial of remission induction with BHAC-DMP failed and patient died in 5 months.