OBJECTIVE To compare the functional results of two contemporary series of patients with clinically localized prostate cancer treated by robot-assisted laparoscopic prostatectomy (RALP) or retropubic radical prostatectomy (RRP). PATIENTS AND METHODS This was a non-randomized prospective comparative study of all patients undergoing RALP or RRP for clinically localized prostate cancer at our institution from February 2006 to April 2007. RESULTS We enrolled 105 patients in the RRP and 103 in the RALP group; the two groups were comparable for all clinical and pathological variables, except median age. For RRP and RALP the respective median operative duration was 135 and 185 min (P < 0.001), the intraoperative blood loss 500 and 300 mL (P < 0.001) and postoperative transfusion rates 14% and 1.9% (P < 0.01). There were complications in 9.7% and 10.4% of the patients (P = 0.854) after RRP and RALP, respectively; the positive surgical margin rates in pT2 cancers were 12.2% and 11.7% (P = 0.70). For urinary continence, 41% of patients having RRP and 68.9% of those having RALP were continent at catheter removal (P < 0.001). The 12-month continence rates were 88% after RRP and 97% after RALP (P = 0.01), with the mean time to continence being 75 and 25 days (P < 0.001), respectively. At the 12-month follow-up, 20 of 41 patients having bilateral nerve-sparing RRP (49%) and 52 of 64 having bilateral nerve-sparing RALP (81%) (P < 0.001) had recovery of erectile function. CONCLUSIONS RALP offers better results than RRP in terms of urinary continence and erectile function recovery, with similar positive surgical margin rates.