Background: Ovarian hyperstimulation syndrome (OHSS) is characterized by collection of fluid in third spaces in in vitro fertilization (IVF) cycles and can result in the cancellation of the cycle and be fatal in 3 women out of 100,000. The aim of this study is to compare the admission of human chorionic gonadotropin (hCG) subcutaneously versus intracavitary during ovum pick-up (OPU) in agonist induced ovulation in IVF cycles in terms of pregnancy outcomes. Methods: This study was carried out in Kocaeli University Faculty of Medicine, Department of Obstetrics and Gynecology Assisted Reproductive Techniques Clinic as a retrospective study. 157 patients who underwent IVF treatment between January 2018 and February 2020, with \ge25 follicles detected in ultrasound and 1 mg of triptorelin acetate was administered for ovulation trigger, and 36 hours later of whom \le20 oocytes were obtained in OPU were enrolled in this study. 109 patients who were administered 1500 IU of hCG subcutaneously belonged to Group 1, and 1500 IU hCG was administered intracavitary to 48 patients as Group 2. Results: Infertility causes, and characteristics of both groups were similar. Number of retrieved oocytes, Metaphase 2 (MII) oocytes and fertilization rates were similar in both groups. Implantation rate per embryo transferred was higher in the intracavitary group (p = 0.01). There was no significant difference for pregnancy rate, clinical pregnancy rate, ongoing pregnancy rate, livebirth rate and OHSS frequency between both groups. Twin pregnancy rate was significantly higher in the intracavitary group. Conclusions: Administration of 1500 IU hCG intracavitary at the time of OPU is associated with improved implantation rates when compared to subcutaneous hCG administration without a significant raise in OHSS occurrence. Prospective, randomized studies with bigger patient cohort are needed.