The goal of this work was to characterize the blood flow in cavernosal-spongiosal communications (CSCs) in patients with erectile dysfunction using color Doppler ultrasound. Peak systolic velocity was measured in the CSCs, cavernosal artery and urethral artery in 72 erectile dysfunction patients of the Han ethnic group in southern China. Blood in the CSCs was observed to flow from the cavernosal artery to the urethral artery in all except 5 patients with arteriogenic insufficiency whose blood flow was bidirectional. Peak systolic velocity in erectile dysfunction patients with normal vascular function or veno-occlusive dysfunction was significantly lower in the CSCs than in the cavernosal artery (p < 0.01), but significantly higher than in the urethral artery (p < 0.05). Peak systolic velocities in CSCs in patients with arteriogenic insufficiency were significantly lower than those in the cavernosal (p < 0.01) and urethral (p < 0.01) arteries. The direction of blood flow in the CSCs is determined by the pressure gradient between the cavernosal and urethral arteries. (C) 2016 World Federation for Ultrasound in Medicine & Biology.