Background: Conventional hemorrhoidectomy leads to a high urinary retention rate and fluid restriction is commonly recommended to minimize complications. However, the need for postoperative fluid restriction among patients who have undergone stapled hemorrhoidopexy is unclear. We aimed to determine whether fluid restriction after stapled hemorrhoidopexy with/without partial external hemorrhoidectomy could reduce urinary retention and postoperative pain.Patients And Methods: In this prospective, double-blinded, randomized controlled trial, we enrolled patients who had grade III or IV hemorrhoids and underwent stapled hemorrhoidopexy with/without partial external hemorrhoidectomy; 250 mL/12 h of sterile 0.9% saline was administered to the fluid restriction group after the operation, and 1000 mL/12 h was given to the non-fluid-restriction group. We focused on the need for fluid restriction after stapled hemorrhoidopexy.Results: Fifty patients were studied in two groups. The surgical outcomes of the two groups were no different. The median subjective pain scores at 0, 8, 16, 24 h after the operation showed no significant difference between the two groups (p = 0.55 at 0 h; p = 0.38 at 8 h; p = 0.98 at 16 h; and p = 0.66 at 24 h). The mean times to first urination after the operation were 700.04 ± 455.03 min in the non-fluid-restriction group and 737.16 ± 426.32 min in the fluid-restriction group (no significant difference; p = 0.67). No postoperative urinary retention was found in either group of patients.Conclusions: Fluid restriction after stapled hemorrhoidopexy is unnecessary.Trial registration: This study was reviewed and approved by the Tri-Service General Hospital Institutional Review Board for human subjects (No. 2-106-05-063). This study also had trial registration with clinicalTrials.gov (Identifier: NCT04459039).