The interaction of gonadotropin-releasing hormone (GNRH) and its receptor(GNRHR) is critical in the endocrine regulation of reproduction. The gene(GNRHR) encoding the receptor has been mapped to porcine chromosome 8. There isevidence for three quantitative trait loci (QTL) influencing ovulation rate onthis chromosome. We obtained an almost complete sequence (3993 bp, excludingintron 1) of the porcine GNRHR gene using PCR-based comparative genomic walkingand inverse genomic walking approaches. Twelve polymorphisms were detected bysequencing of pooled DNA of Chinese Taihu and European Large White pigs,including 7 base substitutions and 5 insertions-deletions (indels). A F2population of Meishan x European Large White pigs was genotyped for a TG indelin the promoter region, and a C/G substitution in the 3' UTR (untranslatedregion). A significant association of the C/G substitution with number ofcorpora lutea at first parity was observed.