The goal of this study was to try to determine the effects of the Botulinum A Toxin on the spasticity of the rhabdosphincter in 9 men with spinal cord injury and detrusor-sphincter dyssynergia. The cystometrography, before and after the endoscopic injection of 100 units of Botulinum A Toxin, consisted of recording the bladder, urethral and rectal pressures with microtip transducers the anatomical position of which was radiographically controlled. The subjective and objective results of that study allow us to conclude that the Botulinum A Toxin has a place in the treatment of spinal injuries with detrusor-sphincter dyssynergia. Due to his blocking effect on the release of acetylcholine in the motor nerve endings, the Botulinum A Toxin suppresses or decreases the spasticity of the rhabdosphincter and improves voiding. Although its relatively short living action (2-3 months) may require renewed injections, it has the advantage to hold off a surgical treatment such as a sphincterotomy and to give the patient another chance to reach a balanced bladder function secondary to the postinjection changes of reflexes which may have taken place between the bladder and the rhabdosphincter and vice versa.