Due to the high incidence of voiding dysfunction (patients with SCI) in the rehabilitation setting, a safe, efficient method for monitoring residual bladder volume is needed. A controlled trial was performed to compare the use of a portable ultrasound unit that calculates bladder volume to catheterization regarding complications, speed of usage and patients feelings. Urethral catheterization, the standard method for measurement of bladder volume is associated with patient discomfort plus risks of urethral trauma and urinary tract infection. A portable ultrasound instrument Bladder Scan 3000 that automatically determines bladder volume was used for 100 patients. This instrument is a noninvasive alternative to urethral catheterization for the determination of bladder volume and it is recommended for clinicians in patients undergoing catheterization programs that can reduce the number of required catheters. It is associated with a high degree of patients satisfaction.