Past attempts at inducing micturition in paraplegics by electric stimulation of the spinal cord micturition center have been generally unsuccessful. Failure has most often resulted from inability to separate the response of the detrusor from that of the sphincter. Because the sacral nerves provide some organizational specificity over the spinal cord and are practically suited to chronic stimulation, experiments were carried out in dogs to find out whether or not stimulation of these roots could induce micturition. Results of acute dog studies did suggest that micturition might effectively be performed by stimulation of the ventral root of the sacral nerve having the greatest detrusor representation. Specificity of bladder response was improved by dividing somatic fibers peripherally. Selected division of somatic fibers from the sacral root stimulated was compared with complete pudendal neurotomy. (The former procedure has the advantage of preserving perineal sensation.) The principles learned from the acute studies were then applied to "chronic" dogs--5 paraplegic and 1 normal. Effective voiding was achieved on a long-term basis. Over-all results were very encouraging. Further research is necessary before application of this technique to humans can be considered.