We describe here the identification and characterization of a human forkhead box gene, FOXK1, that encodes predicted proteins most homologous to the mouse myocyte nuclear factor (MNF)/forkhead box K1 (FoxK1). Human FOXK1 is located at the chromosomal position 7p22. Two transcript variants, FOXK1a and FOXK1b, containing the divergent 5'-ends are identified. Sequence comparison indicated that the human FOXK1 proteins share 66-74% amino acid identity (99% identity in the forkhead domain) with their mouse ortholog. The in silico expression analysis showed FOXK1 expression in immature tissues of brain, eye, heart, lung and thymus. In adults, FOXK1 was predominantly expressed in many malignant tissues, in particular in the tumors of brain, colon and lymph node. This gene is therefore implicated in the process of both normal and neoplastic development.