Purpose of Investigation: To evaluate the effectiveness of single curettage endometrial biopsy injury (EBI) in the proliferative phase for in vitro fertilization-embryo transfer (IVF-ET) outcome of the subsequent cycle in infertile patients with repeated embryo implantation failure (EIF). Materials and Methods: Of 89 patients who repeated EIF three times following transfer of morphologically good embryos and/or blastocysts, 40 patients chose curettage EBI prior to the subsequent IVF-ET cycle. Using a three-mm wide curette, EBI was performed once between days 6 and 12 of the spontaneous cycle. Their IVF-ET outcomes in the subsequent cycle were compared with those in 49 patients who did not opt for EBI. Results: The clinical pregnancy rate (37.5% vs 12.2%), embryo implantation rate (23.6% vs 6.3%), and ongoing pregnancy rate (25.0% vs 8.2%) were significantly higher in the EBI group than in the non-EBI group. No serious complaints and complications were noted. Conclusion: Single curettage EBI in the proliferative phase of the preceding cycle significantly improved IVF-ET outcome in infertile patients with repeated EIF.