In this study, we present a comprehensive 3000-rad radiation hybrid (RH) map of bovine Chromosome (Chr) 26 (BTA26) with 80 markers including 50 genes or ESTs: 44 have an ortholog mapping to human Chr 10 (HSA10) and 29 to mouse Chr (MMU) 7, 10, and 19. Moreover, 12 other HSA10 genes were integrated in a newly developed RH map of BTA28 (seven represent new assignments). The available draft of the mouse genome allowed us to present a detailed picture of the distribution of conserved synteny segments among the three species (human, cattle, and mouse) and to propose a simple model of the comparative chromosomal organization between the long arm of HSA10 and BTA26 and 28. Finally, the INRA bovine BAC library was screened for most of the BTA26 markers considered in this study to provide anchors for the bovine physical map.