Objectives : To compare the presence of telomerase activity(TA) in the chorionic villi between eutopic and ectopic first trimester human pregnancies. Methods : Human chorionic villi were obtained from eleven normal eutopic pregnant women who underwent an elective abortion, and from eleven women with ectopic pregnancy who underwent a salpingectomy for tubal pregnancy. TA was analyzed by radioisotope polymerase chain reaction based telomeric repeat amplification protocol(TRAP) assay. Results : TA was expressed in 5 of 11 (45.5%) in eutopic pregnancies, and in 7 of 11(63.6%) in ectopic pregnancies. Chorionic villi in ectopic pregnancies were expressed more frequently than those of eutopic pregnancies, this difference was not significant.(p>0.05) Conclusion : Our results suggest that the expression of TA in human chorionic villi was not affected according to the implantation site during early placental development.