Fertility traits, such as the ovulation rate and the number of offspring at birth, are genetically regulated by fecundity genes. This study was performed to identify DNA polymorphisms in Booroola (FecB), Galway (FecX(G)), Inverdale (FecX(I)) and Calpastatin (CAST) genes in Sakiz sheep. A total of 71 ewes were genotyped for gene or allelic polymorphisms in the genes listed above using the PCR-RFLP method. The results obtained from this study indicated that all of the Sakiz ewes sampled were non-carriers for FecB, FecX(G) or FecX(I) mutations. However, genotypic frequencies in the CAST gene were 0.59, 0.36 and 0.05 for AA, AB and BB, respectively. A significant deviation from Hardy-Weinberg equilibrium for the CAST gene was not observed in the investigated breed (P>0.05). As a result, more extensive screening is required as tests for newly discovered mutations are developed. Additionally, this study is the first to report a genetic polymorphism in the CAST gene in Sakiz sheep.