Background: Spontaneous unilateral twin ectopic pregnancy is a rare occurrence worldwide, despite the overall increased incidence of ectopic pregnancy as a result of artificial reproductive technology. There are several factors that have led to the overall increase of ectopic pregnancy in many parts of the developed countries. In this paper, we present a case of spontaneous unilateral twin ectopic pregnancy with documented fetal hearts in a woman with a family history of twins and a single documented episode of Chlamydia trachomatis infection. Introduction: A 23-year-old G3P2, presented with an 8-week history of amenorrhea, lower abdominal pain, watery vaginal discharge, and vaginal spotting. During this hospitalization, her serum -HCG testing was 21,000 mIU/mL and a transvaginal ultrasonographic examination suggested a nonviable unilateral twin ectopic pregnancy. Two separate fetal hearts were identified. During laparoscopy, a 10 cm mass involving the right fallopian tube was excised. Pathologic evaluation of the specimen identified one gestational sac, but the second sac was not positively identified because the sacs were crushed following the removal via an endo catch bag or inadequate number of sections by the pathologist; but definite chorionic villi were seen. Conclusions: Mortality and morbidity associated with spontaneous unilateral twin ectopic pregnancy in the fallopian tube could be reduced by prompt diagnosis and management. The resulting distortion caused by acute and chronic pelvic inflammatory diseases is the leading cause of ectopic pregnancy. (J GYNECOL SURG 23:147)