Heterotopic pregnancy (HP) is the existence of both intrauterine and ectopic pregnancy simultaneously. The incidence of spontaneous heterotopic pregnancy is about 1: 30,000 of pregnancies. In this paper the authors presented the case of heterotopic pregnancy, detected at 12 weeks of gestation. Pregnancy was spontaneous and patient was referred to the present hospital due to pelvic pain. After thorough examination, including transvaginal and transabdominal ultrasound, a 12-week heterotopic pregnancy was confirmed. Both fetuses were alive with regular fetal heart rate. Due to possible risk of placental bowel infiltration, laparotomy was performed and right salpingectomy with vital ectopic pregnancy was done. On the left ovary a 2-cm tumor was detected and also removed during operation. Patent was followed up until delivery and was delivered transvaginally at term.