Abstract BackgroundSheep's fecundity is determined by both twinning rate and litter size, both influenced by several genes, one of which is OLR1 (oxidized low-density lipoprotein receptor gene). This study aimed to determine the genetic variation of the OLR1 gene affecting the fecundity traits of Awassi ewes. ResultsTwo genotypes of 334-bp amplicons, CC and CA were detected. In a sequence reaction, the novel mutation p.K116Q was discovered in CA genotypes. There was a highly significant (P ≤ 0.01) association between the single nucleotide polymorphism (SNP) and reproductive traits, in that sheep with the p.K116Q SNP had lower litter size, twinning rate, fecundity, and lambing percentages than individuals with CC genotypes. The ewes with CC genotypes had 1.98 lambs more than those with CA genotypes. These observations imply that the missense p.K116Q variant has an adverse effect on the traits under study. ConclusionsAs such, SNP p.K116Q appears to negatively influence fecundity traits in Awassi sheep. The data evidence that the OLR1 gene variant is one of the most important candidates for marker-assisted selection in the sheep industry.