Heterotopic pregnancies are estimated to be less frequent than one in 30 000 if no assisted reproduction technologies are performed. Here we report a case which occurred in Tanzania. An abdominal pregnancy at term was first misdiagnosed as an ovarian tumour and diagnosed on the first post-partum day of the intrauterine fetus, which was delivered spontaneously. The abdominal pregnancy was then treated by laparotomy and removal of the placenta. The fetus was alive and healthy. The follow-up of the twins was normal.