Congenital factor XIII deficiency is a rare coagulopathy whose prevalence in the world is of the order of one case per 2 million inhabitants. This study made it possible to list the cases of factor XIII deficiency in southern Tunisia and to evaluate the epidemiological, diagnostic and therapeutic aspects. Our study is retrospective, covering a period of 20 years and including 30 patients. A standard haemostasis work-up and factor XIII assay were performed in all our patients. The sex ratio was 0.67. The majority of patients were from Sidi Bouzid. The mean age of onset of symptoms was 1.4 years. The mean age at diagnosis was 8.8 years. 26 patients were diagnosed following a hemorrhagic syndrome and 4 following a family investigation. All had zero factor XIII levels, as measured by the clot solubility technique. All patients received replacement therapy with fresh frozen plasma. The majority of cases were from consanguineous marriages.Therefore, family investigations are of interest to obtain a better epidemiological and molecular profile.