Using genetical markers is one of the best methods to evaluate animal improvement. It is reported that Booroola gene has additive for litter size and ovulation rate in sheep. In this study 125 blood samples were collected from Lory-Bakhteyarian (80 sheep) and Arabian sheep (45 sheep). DNA of blood samples was extracted by modified salting out method. The DNA was evaluated by spectrophotometer and agarose gel. Site of mutation was amplified using specific primers and PCR product (190 bp bands) was determined by agarose gel electrophoresis, and then the products PCR were digested with AvaIl enzyme. The homozygous carrier sheep with FecB mutation (BB) had a 160 bp and 30 bp bands, the noncarriers (++) had a 190 bp bands, whereas heterozygotes (B+) had 160, 30 and 190 bp bands. Results show no polymorphism for FecB gene in khozestanian sheep. All of the sheep were wild type (++), so mutation of FecB gene was not the cause of prolificacy in Khozestanian sheep. Further research is required to evaluate fecundity gene and genotyping of Khozestanian sheep.