Factor XI (FXI) is a protein that plays a key role in plasma coagulation. Factor XI Deficiency (FXID) is an autosomal recessive disease caused by an insertion into exon 12 of FXI gene. The aim of this study is to determine the allele frequency of Factor XI Deficiency (FXID) in Holstein cows reared in Thrace region of Turkey. Blood samples of 287 Holstein cows were used for DNA isolation. Amplification of FXI gene was followed by the evaluation of PCR products with visualization on 2% agarose gel electrophoresis. FXID mutant allele was not observed in any of the samples used in this study. In conclusion, none of the Holstein cows were neither affected nor carriers for FXID among all analysed Holstein cows reared in Thrace region of Turkey.