Cytogenetic studies of acute myeloid leukemia (AML) have revealed that the majority of patients display acquired chromosome aberrations. Numerous recurrent karyotypic aberrations have been and continue to be discovered in AML. Cytogenetic studies have paved the way for molecular analyses that have identified genes involved in the process of leukemogenesis. Moreover, chromosome aberrations, regardless of whether they have been molecularly characterized or not, have been shown to constitute tumor markers of diagnostic and prognostic value. This review presents current information on cytogenetic findings in AML, and correlations between karyotype and clinical features and outcome of de novo AML.