Heterotopic pregnancy is the simultaneous occurrence of intrauterine and ectopic gestations. Possible risk factors include past pelvic inflammatory disease, previous pelvic surgery, or uterine anomalies. Its incidence is very rare, 1 in 30,000 in natural pregnancies but it has been increased in frequency by the advent of assisted reproductive technology. In cases of heterotopic pregnancy with intrauterine pregnancy and ectopic pregnancy, the diagnosis can be even more difficult. And the management of heterotopic pregnancy still remains controversial. We have experienced a case of heterotopic pregnancy with cornual pregnancy after in vitro fertilization and embryo transfer. which was successfully treated by selective fetocide with ultrasonographically guided potassium chloride injection of cornual pregnancy while maintaining the viabillity of the intrauterine gestation.