Résumé : By means of somatic cell hybrids segregating rat chromosomes, we determined the chromosome localization of three rat beta 1 family integrin genes. ITGB1 was assigned to Chromosome (Chr) 19, ITGA4 to Chr 3, and ITGA5 to Chr 7. These chromosome assignments reveal or confirm homology between two pairs of rat and human chromosomes (rat Chr 3-human Chr 2; rat Chr 7-human Chr 12).