¹College of Animal Science and Technology, Shihezi University, Shihezi, Xinjiang, 832003, PR CHINA DOI : 10.9775/kvfd.2017.18194 RXRG (Retinoic X receptor-gamma) gene was originally associated with fetal development and reproduction in human beings and animals, which was used to detect genetic variation that was associated with growth, reproduction, metabolism trait selection and breeding. The aim of this study was to detect RXRG gene mutation of the exon 2 and its association with twinning trait in 313 sheep and calculate litter size, genotype frequency in Chinese Merino, Hu and Kazak sheep. Polymorphism of exon 1, exon 2, exon 10 of RXRG gene in the study were analyzed by PCR-SSCP, which showed that three genotypes of P2 fragment were significantly associated with twinning traits in the analyzed population (P=0.031). Analysis of four groups of sheep showed that there was a predominate gene (B-allele) that have higher twinning rates in these individuals, which indicated that the genotypes can be chosen for twinning according to predominate genotype. In conclusion, our results strongly suggest that polymorphisms of the RXRG gene could be a new choice for sheep breeding and genetics through markerassisted selection (MAS). Keywords : Sheep, Retinoic X receptor-gamma gene, Twinning trait, PCR-SSCP