Amphiregulin (AREG), a glycoprotein that is a member of the epidermal growth factor (EGF) family, is expressed by the porcine conceptus and endometrium. AREG genotypes were determined based on an SNP in the intron 3 of the gene. Contradictory effects of AREG genotypes on reproductive traits in different pig breeds were reported previously. G allele had undesirable effect on reproductive trait in Meishan breed, while it had favorable effects in Polish Landrace and Large White. We determined AREG genotypes of 179 pigs including the Duroc, Landrace, Yorkshire, Korean native pig (KNP), and Meishan breeds. Two new SNPs were identified near the previously reported SNP in the intron 3 of AREG. Frequencies of AREG alleles among the Duroc, Landrace, Yorkshire, and KNP sows were significantly different (p<0.001), indicating association between AREG genotypes and pig breeds. The first parity litter size was significantly affected by the breeds (p=0.014), but not by AREG genotypes (p=0.148). However, there were breed and AREG genotype associated trends in the first parity litter size. The first parity litter size appeared to be higher in Duroc and KNP sows with G allele, while it appeared to be lower in Landrace sows with G allele. Significant variability of AREG alleles among pig breeds, for the first time in Duroc and KNP sows, was identified. AREG genotypes may influence reproductive traits differentially for each breed and thus, AREG genotypes may need to be considered when sows are bred to increase litter size.