Spontaneous twin ectopic pregnancy is extremely rare. Among more than 100 reported cases of twin tubal pregnancies, successful treatment with methotrexate has yet to be reported. A 26-year-old nulliparouswomanwas admittedwith vaginal bleeding and abdominal pain. She had previously undergone infertility treatment using ovulation induction with gonadotropins and intrauterine insemination. On admission, the patient's serum level of beta-human chorionic gonadotropin (β-hCG) was 763 IU/mL. Two gestational sacs were observed in the left tube on transvaginal ultrasound. An increase in serum β-hCG level was observed on the third day of hospitalization. A multiple-dose regimen of methotrexate (1 mg/kg of methotrexate on days 1, 3, 5, and 7, and 0.1 mg/kg of folinic acid on days 2, 4, 6, and 8) was begun when the patient's β-hCG serum level reached987 IU/mL.On day1 ofmethotrexate treatment, dilatation and curettage was performed and endometrium without chorionic villi was reported by the pathologist. Serum levels of β-hCG reached 1091 IU/mL on day 2, 1219 IU/mL on day 4, and 750 IU/mL on day 6. A single dose of methotrexate (1 mg/kg) was repeated on the 14th day as the serum level of β-hCG reached 1200 IU/mL. Serum β-hCG levels declined to within the normal range 32 days after initiation of the treatment. The main risk factors in this case are infertility treatment and smoking. Marcovici et al. [1] showed that conventional methotrexate treatment was unsuccessful for spontaneous bilateral tubal ectopic pregnancies, while hemodynamically stable unruptured tubal ectopic pregnancies and heterotopic pregnancies could be successfully treated with systemic methotrexate [2]. The present case reports a unilateral twin tubal ectopic pregnancy treated successfully using systemic multiple doses of methotrexate.