Background: Missed abortions are a common problem, often caused by thrombophilia in both recurring and non-recurring cases. Aim: To determine whether the presence of a mutation in the methyltetrahydrofolate reductase (Mthfr) gene correlates with missed abortions. Patients and methods: We selected two hundred patients for this study in two groups: the study group, which consisted of one hundred patients with a history of missed abortion; and the control group, which consisted of one hundred patients with no history of missed abortion. Results: Of the 200 patients, mutations in Mthfr were only found in forty-four patients—thirty-four from the study group and ten from the control group. Conclusions: Mthfr gene mutation is a common cause of both recurring and non-recurring missed abortions.