The PAX8 gene, a member of the human paired box gene family, was mapped by FISH to chromosome 11 in cattle and goat and to the short arm of chromosome 3 in sheep. The cytogenetic position of PAX8 on BTA 11 and on its homologue OAR 3p lies in the region where the interleukin beta (IL1B) gene has been previously located, (BTA 11q22. 1-->q22.3 and OAR 3p25-->q26 respectively; Lòpez-Corrales et al., 1998). The results indicated that PAX8 as well as interleukin beta and interleukin alpha (IL1B and IL1A) genes detected on the human chromosome segment HSA 2q13-->q21 maintain a similar order and location in these three related species. In addition, the breakpoint in conserved synteny can now be narrowed to a position between the protein C (PROC) and PAX8 genes, which lie in close proximity on HSA 2.