Our aim was to study expression levels of the NF-κB1 gene family in Ukrainian B-cell chronic lymphocytic leukemia (B-CLL), B-cell non-Hodgkin’s lymphoma (NHL), acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), chronic myeloid leukemia (CML), hairy cell leukemia (HCL), and T-cell large granular lymphocytic leukemia (T-cell LGLL) patients in the post-Chernobyl period. This evidence concerns the gene NFKB1 and hairy cell leukemia.