We herein report a case of cornual viable pregnancy that was successfully treated with a single dose methotrexate without the need for surgical intervention. A 37 year-old woman was diagnosed cornual pregnancy based on transvaginal ultrasound findings and hormonal assays. A single dose systemic methotrexate (50 mg/m2) was administered. No side effects were experienced. Early diagnosis of interstitial pregnancy can lead to conservative treatment options. Although the most effective methotrexate protocol for conservative treatment is uncertain we concluded that in the hemodynamically stable patient a single dose systemic methotrexate treatment is a useful and should be considered as the first line treatment. This is safe and highly effective management even though viable fetus or high level of human chorionic gonadotropin (B-hCG) was assigned. Hemodynamic stability is the most important criteria and that is directly correlated with the early diagnosis. Surgery can be avoided; however, with conservative management a longer and close follow-up is required.