We aimed to investigate sperm retrieval rates (SRR) by testicular sperm extraction (TESE), factors affecting SRR, and fertilization rate (FR), implantation rate (IR), clinical pregnancy rate (CPR) and live birth rate (LBR) in patients with presumed Sertoli-cell-only syndrome in testis biopsy (SCOS). We retrospectively evaluated files of 134 patients with SCOS who underwent TESE. Group I were patients in whom spermatozoa were retrieved and Group II were patients in whom no spermatozoa could be retrieved. SRR, Follicle stimulating hormone (FSH), Luteinizing hormone (LH), and testosterone levels, and the volume of testicles were compared between groups. In addition, FR, IR, CPR and LBR were determined. Sperm retrieval was achieved in 37 (27.6%) patients (Group I), and the remaining 97 (72.4%) patients made Group II. There were no significant differences in age, infertility time, testicular volume, serum FSH, LH and testosterone levels between Groups I and II (p > 0.05). Intracytoplasmic sperm injection (ICSI) was performed in 36 patients. FR, IR, and CPR were 60.86 ± 23.03, 36.53 ± 41.78 and 51.3% respectively. Cycle and patient based LBRs were 37.8 and 45.1% respectively. SRR in SCOS is lower than patients with non-obstructive azoospermia (NOA) in general. No parameters to predict spermatozoa retrieval were determined. In patients with SCOS, ICSI achieves similar live birth rate to other patients with NOA.