Objectives: The objective of this study was to analyze the pre-operative and intra-operative variables that can condition urinary incontinence (UI) after radical prostatectomy (RP), as well as continence rate recovery during a pelvic floor rehabilitation program. Materials and Methods: A total of 72 cases with UI after RP were prospectively examined. All cases were homogeneously treated by the same surgeon, using the same RP technique. A combination of biofeedback (BF) and pelvic floor electric stimulation (PFES) performed by the same clinician and using the same protocol was used. Clinical, pathologic and surgical variables were analyzed in terms of 24 h pad test results (pad weight and pad-free status). Results: Prostate volume (PV) strongly varied from 24 to 127 cc (mean ± SD 46.39 ± 18.65 cc), and the baseline pad weight varied from 10 to 1500 cc (mean ± SD 354.29 ± 404.15 cc). PV strongly and positively correlated with the baseline pad weight (r = 0.4215; p = 0.0269) and inversely with the three-month pad weight (r = − 0.4763; p = 0.0213) and pad-free status (r =− 0.3010; p = 0.0429). The risk of a residual pad weight >10 g after the rehabilitative program significantly increased according to PV (p = 0.001) and the baseline pad weight (p = 0.002 and < 0.0001). In particular, PV > 40 cc and a baseline pad weight >400 g significantly (p = 0.010 and p < 0.0001, respectively) and independently predicted a 5.7 and a 35.4 times increase in the risk of a residual pad weight at the three-month follow-up, respectively. Conclusion: This is the first prospective trial whose primary objective is to verify the possible predictors, such as PV, that are able to condition the response to a pelvic floor rehabilitation program for UI after RP.