Proliferation of abnormal hematopoietic cells with impaired differentiation, regulation and programmed cell death leads to leukemia. AML(acute myeloid leukemia) is a malignancy with malfunction of myeloid hematopoietic cells with acute behavior. The oral manifestations of the disease are posterior palate hemorrhage, gingival bleeding and gingival ulceration as a result of infection by normal oral flora and gingival infiltration by leukemic cells. A 49-year-old male patient was referred from local dental clinic. The patient was diagnosed with AML FAB M1 (acute myeloid leukemia French-American-British classification M1 myeloblastic leukemia without maturation). The oral infection focus was removed by a conservative treatment. 2 days after the dental treatment, the patient underwent chemotherapy. At 8-month follow-up, the overall outcome was excellent. Oral manifestations of AML are often the first indications of the malignancy. Therefore it is essential for dentists, especially oral and maxillofacial surgeons, to be aware of the diagnostic signs and complications associated with leukemia for better diagnosis and subsequent treatment and management.