TheTFDPgenes encode a family of transcription factors that can form heterodimers withE2Ffamily proteinsin vivo.The E2F–TFDP transcription factors are major regulators of genes that are required for the progression of S-phase, such as DHFR and DNA polymerase α, and they play a critical role in cell cycle regulation and differentiation. The retinoblastoma tumor suppressor protein has been shown to induce growth arrest by binding to E2F-TFDP and repressing its activity. Two humanTFDPgenes have been cloned, namelyTFDP1andTFDP2(or DP1 and DP2). In the present study, we identified genomic clones ofTFDP1,its pseudogeneTFDP1PandTFDP2,and we mapped them to chromosome 13q34, 1q32.3, and 3q23, respectively. Chromosomal abnormalities involving regions 13q34 and 3q23 have been reported in certain lymphomas and other diseases associated with loss of cell cycle regulation, and the involvement of theTFDPtranscription factors remains to be elucidated.