PURPOSE: To compare reproductive outcomes following conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in poor responders fulfilling the Bologna criteria, with a single oocyte retrieved.METHODS: The present retrospective study included 243 Bologna poor responders with a single oocyte retrieved, who were categorized into three groups, depending on the fertilization method and semen quality (IVF non-male factor-IVF/NMF n = 101; ICSI non-male factor ICSI/NMF n = 50; ICSI male factor-ICSI/MF n = 92).RESULTS: In IVF/NMF, ICSI/NMF and ICSI/MF similar fertilization rates [65.3, 66, 58.7%, respectively], proportions of embryo formation [63.4, 60, 53.3%, respectively], proportions of good quality embryos [54.7, 56.7, 57.1%, respectively], implantation rates [8.9, 10, 8.2% respectively] and live birth rates per oocyte retrieval [5.0, 4.0, 3.3%, respectively] were observed. Degeneration rate of oocytes due to mechanical damage was significantly higher after ICSI in the ICSI/NMF and ICSI/MF groups (8 and 6.5%, respectively) compared to IVF/NMF (0%) (p = 0.02).CONCLUSIONS: Conventional IVF and ICSI are associated with similar reproductive outcomes in poor responder patients with a single oocyte retrieved. Therefore, the choice of fertilization method should be based primarily on semen quality, in combination with the patient's previous history. A randomized controlled trial should be performed to confirm this study's findings that conventional IVF and ICSI have similar reproductive outcomes in poor responders.