This is the case of an 62-year-old man who had symptoms such as splenomegaly +10 cm below the costal arch, very high WBC (169*10/9/L), immature granulocytes in CBC ( 7%), low PLT count (85*10/9/L), low HGB level (11.2 g/dL) and monocytosis (22% or 37*10/9/L). He was admitted to hematology clinic in our center. He also presented with hypercellularity with high count of monocytes in bone marrow (18%) and the blasts count was 7%. We did cytogenetic test of bone marrow by standard method. The karyotype was 48, XYY, +13 . In additional we did cytogenetic analysis of lymphocytes stimulated by phytohaemagglutinin. The final cytogenetic conclusion showed that the patient had XYY syndrome or “superman” syndrome. This is rare congenital genetic disorder which often becomes unrecognized. The patient received final hematological diagnosis of Chronic Myelomonocytic Leukemia-1 by WHO 2017 classification. Therapy was invited with Hydroxyurea during 6 months without remission and with progression to acute myeloid leukemia. The second line was chemotherapy of 6-mercaptopurinum and low doses of cytarabine. In spite of treatment, the patient ultimately died from progression AML. It is known, that patients with some different congenital genetic disorders, such as Dawn`s syndrome, Fanconi anemia, severe congenital neutropenia, Shwachman-Diamond syndrome and others, have high risk of leukemia. However, there are very little clinical cases described in science press. It was one of these rare cases. So, can “superman” have a CMML? Yes, if he has acquired trisomy 13.