Background: This article describes a case of heterotopic pregnancy that included a normal twin intrauterine pregnancy and one cesarean section (CS) scar pregnancy diagnosed at 6 weeks of gestation. Ultrasound-guided aspiration of the ectopic gestational sac was performed, and the concurrent twin intrauterine pregnancy (IUP) was preserved successfully. The patient was a 50-year-old woman with secondary infertility. Case: The patient underwent in vitro fertilization and embryo transfer using a donor-egg program to achieve pregnancy with her current partner. At 6-weeks' gestation, she underwent a transvaginal ultrasound scan (US) examination showing a viable twin IUP with a third gestational sac with viable embryo located low within the anterior wall of the uterus. The appearance was consistent with a cesarean scar ectopic pregnancy. This was confirmed on a subsequent US 1 week later. She desired to continue the intrauterine pregnancy. US-guided aspiration of the cesarean scar ectopic pregnancy was attempted. The treatment was successful. Results: The twin pregnancy progressed without further complications. Conclusions: Heterotopic CS ectopic pregnancy can be successfully treated with transvaginal US-guided aspiration.