The study included 18 men, submitted to urodynamic investigation 9-18 months after cystoprostatectomy for bladder cancer and bladder substitution with a detubularized ileal segment as described by Studer-Zingg. Sixteen patients were continent by day and 3 were incontinent during the night so as to require the use of a condom catheter. The residual urine was over 100 ml in 3 patients, while it was low or absent in the remainder. Micturition was performed by straining, and maximal flow rates were normal, although the pattern was intermittent. The incidence of nocturnal incontinence was 55.5%. Measurement of the urethral pressure profile revealed a shortened functional length, and low pressure was found in 3 patients, with a maximum urethral closure pressure < 45 cm H2O. During extramural ambulatory urodynamic monitoring, pressure values in the neobladder usually ranged below 20 cm H2O and exceeded 34 cm H2O in only 2 patients who complained of daytime and nocturnal incontinence. The urodynamic features of the neobladder in patients who underwent radical cystoprostatectomy and bladder replacement with a detubularized ileal segment indicate low pressure at high-level filling.