OBJECTIVE: To evaluate the inhibition effects of hyper-reflexic detrusor activity by sacral afferent nerve stimulation in spinal cord injury (SCI) patients. METHOD: The subjects were thirteen patients with SCI who had symptoms of urinary incontinence, because of hyper-reflexic bladder contractions. According to the level and severity of injury, the patients were divided into groups of tetraplegia/paraplegia and complete/incomplete. We applied dorsal penile nerve (DPN) stimulation using portable stimulator during the continuous bladder filling. Stimulation parameters were biphasic rectangular pulses of 25 Hz frequency, 250 microseconds pulse width. Stimulation intensity was twice the threshold of pudendo-anal reflex. The one minute stimulation was repeated to every reflex contraction during the cystometry. Immediate suppressive effect of DPN was analyzed. RESULTS: Of 13 patients who had a reflex bladder, hyper-reflexic detrusor contractions were suppressed effectively in 12 by DPN stimulation. The suppressive effect in groups of level and severity was not statistically significant. CONCLUSION: DPN stimulation for inhibition of hyper-reflexic bladder contraction is an adjunctive method of incontinence management in SCI patients of different level and severity.