Purpose : To investigate the effect of ultrasound-guided embryo transfer on the rate of implantation and clinical pregnancy. Methods : A prospective randomized trial was performed to compare ultrasound-guided embryo transfer with the traditional method. A total of 330 patients were randomly divided into two groups on the day of embryo transfer. For the cases (n = 178), ultrasound-guided was used; controls (n = 152) was performed using routine methods. Results : The rate of implantation and clinical pregnancy for the cases (19.6 and 37.1%, respectively) was significantly higher than for the controls (12.6 and 25%, respectively; p < 0.05). Conclusion : Ultrasound-guided embryo transfer can significantly increase the rate of implantation and clinical pregnancy, and should be recommended as a routine procedure in the process of in vitro fertilization and embryo transfer (IVF-ET).