Background: Acute Megakaryocytic Leukemia (AML-M7) is a subtype with 1% incidence of all adult AML cases. Variation morphology and limitations of immunophenotyping often make AML-M7 difficult to diagnose. The diagnosis of AML-M7 requires morphology and immunophenotyping. This case will discuss about immunophenotyping profile in establishing AML-M7 in an adult patient. Case Description: A 32-year-old-male, presented with fever, dizziness, loss of appetite and weakness on extremities, signs of bleeding were not found. Physical examination showed conjunctival anemia and decrease of power extremities. Laboratory results showed Hb 5.3 g/dL, WBC 79,700/?L, PLT 9,000/?L, IPF 37.3%. Blood smear evaluation and bone marrow aspiration resulted in dry tap but obtained formation resembling abnormal micro megakaryocytes and lymphoid cells. Immunophenotyping results were positive on megakaryocytes specific antigen CD 61 and CD36, as well as myeloid markers CD33, CD13, and CD117. Negative results of lymphoid markers were CD3 and CD79a. Patient did not receive chemotherapy and refused treatment. Two days after the patient passed away. Conclusion : AML-M7 cases in adult patients are very rare. Morphologies are very varied. In this case, morphology of blasts was difficult to distinguish with lymphoid cells because cytoplasm bleps were found. Immunophenotyping results showed positive CD61 and CD36 and negative lymphoid markers (CD3, CD79a) according to AML M7. Myeloid markers were positive in this case. Thus, it is concluded that this case was AML-M7 .