AIM: One of the main problems concerning repeated spontaneous miscarriage (RSM) is the etiological diagnosis. The relation of thrombophilia to RSM is a matter of debate. In this case-control study, we determined the percentages of three thrombophilic mutations (factor V leiden, prothrombin, and methylenetetrahydrofolate reductase) amongst 20 cases with RSM and 20 control normal parous women. RESULTS: There were high statistically significant increases in the number of cases with factor V, prothrombin, and methylenetetrahydrofolate reductase gene mutations compared with normal control and the percentage of multiple gene mutations was higher than single gene mutation. CONCLUSION: The prevalence of thrombophilic mutations is higher in cases of RSM than control.