Heterotopic pregnancy has been traditionally considered a rare event; however, with the use of assisted reproductive technology, the incidence of heterotopic pregnancies is increasing. Early diagnosis of heterotopic pregnancy is often difficult because clinical symptoms and signs are not specific. We experienced two rare cases of heterotopic pregnancy following in vitro fertilization and embryo transfer. First case was the triplet pregnancy, which was combined one intrauterine pregnancy and two extrauterine pregnancy in bilateral tube. Second case was the unruptured heterotopic pregnancy by midtrimester, which had not any symptom and was diagnosed by ultrasound. We report two cases of rare heterotopic pregnancy following in vitro fertilization with brief review of literature.