OBJECTIVE To determine the urodynamic characteristics of urinary incontinence after radical retropubic prostatectomy. METHODS We conducted a clinical and urodynamic study on 25 patients who had undergone radical retropubic prostatectomy due to localized prostate adenocarcinoma. RESULTS 68% of the patients completely recovered urinary continence. The maximum rate of urinary continence recovery was found between the third and fourth month postprostatectomy. A relationship was demonstrated between preoperative hormone blockade, duration of the surgery and urinary continence. Videocystography demonstrated an incompetent proximal continence mechanism in all radical prostatectomy patients. All incontinent patients presented stress urinary incontinence. Denervation potentials of the periurethral sphincter was demonstrated by electromyography in 80% of incontinent patients. These potentials were not present in the continent patients. Reinnervation potentials were present in 50% of the continent patients and in 20% of the incontinent patients (significant differences). No relationship was found between other urodynamic data and post-radical prostatectomy urinary incontinence. CONCLUSIONS The surgical difficulty influences the preservation of urinary continence. A high percentage of patients submitted to radical prostatectomy recover urinary continence with time. Urinary incontinence following radical prostatectomy is based on the distal sphincteric mechanism. Patients who remain incontinent four months postoperatively and with electromyographically demonstrated denervation potentials of the periurethral sphincter can be considered to be candidates for treatment of incontinence without waiting any further.