To assess the role of bladder emptying on outcomes of males undergoing transurethral resection of the prostate (TURP).This prospective study involved candidates for TURP (January 2017-2018) with a follow-up of 3 years. Preoperative and follow-up evaluation comprised: UF, simple PVR (S-PVR), PVR-Ratio (PVR-R) as the ratio of PVR to bladder volume (BV: voided volume (VV) + PVR), Bladder voiding efficiency (BE) as the ratio between VV and BV -(voided volume/total bladder capacity) × 100 - and the IPSS. Patients were stratified for S-PVR, PVR-R, and BVE.Patients recruited were 100 (mean ± SD age: 68.8 ± 8.7 years). No patient had severe complications, re-admission, nor needed blood transfusion. At baseline, 38% of the patients showed S-PVR ≤ 50 mL, 62% a S-PVR ≤ 100 mL, and 25% a S-PVR150 mL. In both pre- and postoperative evaluation there were no significant differences in Qmax and IPSS score among the groups. In each group we found a significant improvement in Qmax, IPSS score, and S-PVR, PVR-R and BVE after TURP (except for PVR in group with lowest preoperative S-PVR). Analysing a preoperative S-PVR threshold100 mL, PVR-R significantly increased, and BVE significantly decreased after TURP. Conversely, when preoperative S-PVR was100 mL, PVR-R, and BVE relevantly but non significantly improved after surgery.Bladder emptying is only partially related to TURP outcomes and other preperative parameters. Patients with baseline S-PVR lower than 100 mL had the chance of greater recovery of bladder emptying after TURP.