OBJECTIVE Male stress incontinence is mainly caused by sphincter lesions, representing the majority of incontinent patients after retropubic radical prostatectomy (RRP). Reflecting the sphincter activity, the urethral pressure profile (UPP) was used to evaluate 65 consecutive patients 6 months after retropubic RRP to identify patients with persistent sphincteric incontinence. METHODS According to the history of continence, patients were divided into a continent group and three incontinent subgroups. Six months postoperatively, spontaneous flow and two cystometries were performed with a filling rate of 60 ml/min, immediately followed by pressure flow and two UPPs, flow rate 1 ml with a pulling rate of 2 mm/s, focusing on functional length (FL) and maximal urethral closure pressure (MUCP). At 6 and 12 months' follow-up, questionnaires were filled in concerning the present state of continence. RESULTS After RRP, two-thirds were continent after 6 months, whereas one-third still suffered from incontinence. MUCP and FL in the stress incontinent group had decreased significantly compared with the continent group (66.2+/-26.4 vs 21.0+/-13.6 cmH(2)O, p< or =0.001; and 11.4+/-3.7 and 8.2+/-3.7 mm, p=0.05), accompanied by a characteristic UPP configuration. After 12 months subgroups of sphincter incontinence and bladder and sphincter combined experienced no change, whereas the group with bladder incontinence achieved satisfactory improvement. CONCLUSIONS Postoperative urodynamics after 6 months may be predictive for persistent incontinence at the bladder, sphincter, and both, suggesting that immediate intervention is more appropriate than watchful waiting. Sphincter incontinence was diagnosed by stress incontinence with MUCP below 30 cmH(2)O, decreased FL and a distinctive profile.