The purpose of this study is to evaluate the influence of endometrial biopsy on increasing implantation rate in patients with recurrent implantation failures, 93 women with at least two implantation failures were evaluated. In case group endometrial biopsy was obtained from 48 patients in the luteal phase of previous cycle and implantation and clinical pregnancy rate were compared with 45 patients in control group. The results suggest that in vitro fertilization or intracytoplasmic sperm injection after endometrial biopsy increase pregnancy outcome.