Acute myeloid leukemia (AML) is characterized as a heterogeneous disease where the patients are sub grouped according to several classification systems and mutational analyses. Diagnosis of AML is based on identification of the specific myeloid cell initiating the disease, quantification of immature blasts in bone marrow and peripheral blood, as well as detection of mutations and translocations. The heterogeneity of AML is caused by a block in differentiation that may occur in any of the different myeloid cell populations. These undifferentiated cells also harbor an increased proliferation potential that leads to accumulation of immature leukemic cells. The current development of more sensitive and less labor intensive analysis methods has led classification of patients from being a system based on morphology of the leukemic cells to being more sophisticated, detecting translocations and small mutations found in the whole leukemic clone or in a minor subclone. This review aims to describe the most common classification systems of AML, including frequently occurring translocations, mutations and epigenetic alterations, as well as describe traditional and novel methods for diagnosis and analysis of these patients.