Voiding dysfunction may be assessed using the intravenous urodynamogram (IVUD) or combined with pressure studies in the videocystometrogram (VCMG). However, VCMG requires bladder catheterization and voiding in public which often leads to inhibition of sphincter relaxation. For this reason the urinary flow rate measurement performed in private is more representative of the true voiding pattern. The ultrasound cystodynamogram (USCD) evaluates the bladder capacity, mean and maximum flow rates, flow pattern and post-micturition residual. The diagnostic capability of USCD was studied in 116 consecutive cases 46 of whom had also had VCMG. Comparison of the data obtained using both techniques revealed no significant difference. USCD has proved to be accurate, safe and reproducible and is of particular value in patient follow-up.