Background:Recurrent pregnancy loss (RPL) is a heterogeneous condition consisting of two or more consecutive abortions occurring before 20 weeks of gestation. One of the clotting factor genes encodes factor XIII (Methods:A prospective case-control study was performed on a cohort of 310 RPL patients and 290 healthy controls. DNA was extracted from the whole blood and fragments of the Val34Leu polymorphism were amplified by polymerase chain reaction (PCR), followed by DNA sequencing. Genotyping was performed using the Sequenom MassArray system.Results:The genotype frequencies ofConclusions:No significant association was observed between the Val34Leu polymorphism and RPL among Iranian Azeri women.