Myeloid malignancies can be either primary or secondary, whether or not a specific cause can be determined. Fanconi anemia (FA), a rare constitutional bone marrow failure, usually presents an increased possibility of clonal evolution, due to the increase in chromosomal instability, TP53 activation, and cell death. The evolution of FA may include aplastic anemia by the progressive failure of the bone marrow and myelod neoplasias, such as acute myeloid leukemia and myelodysplastic syndrome. Chromosome abnormalities, particularly of chromosomes, 1, 3, and 7, during the aplastic phase of the disease are predictive of evolution to acute myeloid leukemia/myelodysplastic syndrome. Cytogenetic studies are indispensable to characterize chromosome abnormalities, and thus an important part of the clinical management, and for planning of therapeutic interventions. Here, clinical data and outcomes of 4 FA, 3 of them with myeloid malignances and 1 asymptomatic, and detailed characterization of their chromosome abnormalities using cytogenetics techniques are described.