We report a patient with polycythemia vera whose bone marrow cells carried a novel t(16;20)(q22;p13) as detected by karyotype analysis using G- and Q-banding techniques. The reciprocal translocation was confirmed by fluorescence in situ hybridization (FISH) using DNA libraries of chromosomes 16 and 20. To our knowledge, t(16;20)(q22;p13) has not been reported previously. The core binding factor beta (CBFbeta) gene located on 16q22 is known to be frequently involved in acute myelocytic leukemia. On the other hand, the 20p13 locus contains a gene encoding protein kinase CK2alpha, which is closely related to cell proliferation and cell cycle regulation. The t(16;20)(q22;p13) may be one of the cytogenetic aberrations in myeloproliferative disorders, and therefore, our observation warrants further studies on a possible involvement of the genes resulting from this translocation.