On the basis of several hundreds of urodynamic investigations done in 105 SCI patients the phenomenon of urethral sphincter dyssynergia was studied. In Upper Motor Neuron Lesion (UMNL) patients, dyssynergic contractions of the external urethral sphincter during spontaneous bladder contractions were demonstrated in 86% and, during bladder contractions initiated by suprapubic tapping, also in 86%. CREDE manoeuvre or abdominal straining gave an augmentation of the urethral sphincter activity in 53%. Interrupted tapping could lower a dyssynergic sphincter activity in a great number of UMNL patients. This technique of bladder stimulation was important to acquire a balanced bladder function in 28% of the patients. In patients with a non-contracting detrusor, a non-relaxing sphincter or augmentation of the sphincter spasticity with the crédé manoeuvre or abdominal straining was found in at least 50%. The values of different forms of conservative treatment and of sphincterotomy are discussed. The final outcome of the bladder reeducation is given.