The aims of the present study were to investigate the impact of research subjects' characteristics on the accuracy of the BladderScan when the latter is used to measure post-void residual urine volume, and to evaluate differences between BladderScan and catheterization in terms of the expenditure of time and of human and material resources. Subjects in the present study were 71 patients undergoing inpatient or outpatient rehabilitation therapy. Post-void residual urine was measured with the BladderScan BVI 3000, followed by intermittent catheterization. Repeated- measures ANOVA revealed no statistically significant difference between the post-void residual urine volume measured by the bladder ultrasound and that of catheterization, or among the factors: sex, diagnosis, body position, thickness of abdominal fat, bladder shape, urine volume, and time intervals between operations. The BladderScan averaged 45 seconds (range=17-119 seconds), while catheterization averaged 293 seconds (range=136-664 seconds); the time required for catheterization was 3 to 8 times that for the BladderScan. The BladderScan gave accurate measurements of post-void residual urine volume for all of the subjects. Using the BladderScan first to measure post-void residual urine volume can reduce the frequency of catheterization, and can save medical human resources costs as well.