Background: Congenital factor XIII (FXIII) deficiency is a rare severs autosomal recessive bleeding disorder.

Objectives: The aim of the study was to determine the c559T > C FXIIIA genotype frequency in patients with FXIII hemophilia who lived in Sistan and Balouchestan province in southeast of Iran.

Patients and Methods: We determined the genotype of 180 patients with Factor XIII hemophilia by tetra-primer amplification refractory mutation system-polymerases chain reaction (T-ARMS-PCR).

Results: The frequency of C559T > C was 96.6% and T-ARMS-PCR was an efficient tool for detecting this genotype. Moreover, the result showed that C559T > C mutation was a risk factor for FXIIIA deficiency in a sample of Iranian population.

Conclusions: Due to highest prevalence of FXIII deficiency (70 times higher than the global average), FXIII deficiency must be consider as the most underdiagnosed bleeding disorder in this area. Hence, proper screening systems alongside common screening tests to identify carriers seem necessary. Due to the limited mutations, T-ARMS-PCR with sound speed, accuracy, sensitivity, and cheapness can be used to screen for these mutations.