Heterotopic pregnancy, defined as the coexistence of an intrauterine pregnancy and an ectopic pregnancy, occurs in approximately 1 in 100 pregnancies conceived by in vitro fertilization (IVF), particularly when multiple embryos are transferred into the uterus. The ectopic gestation of the combined pregnancy usually occurs within the ampulla of the fallopian tube. If it implants within the interstitial portion of the fallopian tube, however, the resulting interstitial pregnancy eventually can rupture through the uterus, leading to sudden, severe hemorrhage and materhal death. This article describes the rupture of an interstitial heterotopic pregnancy in a 37-year-old woman conceiving by IVF after bilateral salpingectomy. The interstitial pregnancy was removed by laparotomy to protect the intrauterine pregnancy from damage. Physicians should consider interstitial ectopic pregnancy as a cause of abdominal pain, even when a viable pregnancy occurs by IVF after salpingectomy.