Below, we discuss IFN-α’s role in treatment of the main myeloid malignancies: the myeloproliferative neoplasms (chronic myeloid leukemia (CML), polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), as well as in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). This evidence concerns the gene IFNA1 and chronic myelogenous leukemia, BCR-ABL1 positive.