BACKGROUND: Robotic-assisted radical prostatectomy (RARP) is widely used as the main surgical approach to treat prostate cancer in the United States. Prostate size is often described as a factor affecting the outcomes of RARP as shown by many studies. However, these studies are limited to a small number of patients. OBJECTIVE: To evaluate the functional and oncologic outcomes of RARP in very large prostate sizes. METHODS: Three hundred and seventy-five RARP patients were divided into two groups according to prostate size: Group 1 had prostates larger than 150 g and Group 2 smaller than 50 g. Perioperative variables were matched with propensity score matching 1:3 and postoperative variables were analyzed for significant differences in outcomes between groups. Variables analyzed included estimated blood loss (EBL), operative time, catheter time, hospitalization time, postoperative complications, pathological staging, positive surgical margins (PSM) rates, biochemical recurrence (BCR), potency, and continence rates. RESULTS: The two groups exhibited similar preoperative characteristics. Patients with larger prostates (Group 1) were more likely to have higher blood loss (EBL), longer console time, and more days with catheter. However, we could not find significant difference in the overall postoperative complications (Clavien-Dindo). Pathological outcomes were also statistically different as patients with larger prostates had (69.7%) more pT2 disease and (12.1%) lower rates of PSM. Finally, we could not find significant difference in the functional outcomes between the groups. CONCLUSION: The results demonstrate that prostate size impacts multiple outcomes. Larger prostates had lower-grade disease, reduced EPE and PSM rates, with no significant differences in BCR or functional outcomes. Perioperative differences, such as increased blood loss and console time, were also observed.