Many cytoplasmic processes of megakaryocytes were seen in a 45-year-old male patient of Munchausen syndrome with sustained severe anemia due to repeated self-blood drawing. He had a past history of repeated infection and removal of skin-graft transplanted for giant congenital melanocytic nevus due to self-infliction (later confessed by the patient). On the admission, he presented with high fever (39 approximately 40 degrees C) and severe sustained anemia refractory to repeated blood transfusions. Any specific clinical data indicating bleeding or hemolysis were not found. Self-blood drawing was discovered by a nurse on his 27th hospital day. Syringes and needles for blooddrawing were also found. He recovered from anemia under intensive watching without any specific treatment. He confessed that the high fever was artificial. It was of interest that cytoplasmic processes of megakaryocytes were seen in the peripheral blood film until he recovered from anemia for one month. The serum level of erythropoietin was elevated (1540 mU/ml), but not significantly was that of thrombopoietin (1.54 fmol/ml). This case was considered to be valuable to understand the mechanism of platelet-production by megakaryocytes at persistent bleeding.