Spasmodic dysphonia is a focal dystonia that effects the proximal muscles (adduction dystonia) or dilatory (abduction dystonia) of the larynx. Botulinum toxin (BTX), generally delivered by percutaneous injection, is the treatment of choice. Recently, use has been made of a transoral route of delivery, with BTX injected through a curved device with visual control. It remains to be determined which route is better. Percutaneous injection is simple and well-tolerated, but the transoral route is theoretically more effective. We assessed the efficacy of both techniques in 19 patients with adduction dystonia, conducting 55 treatment sessions by percutaneous injection and 20 by transoral injection. All the transoral treatments were effective (20/20, 100%), but only 81% (45-155) of the percutaneous treatments were (p < 0.05). Two patients who had doubtful responses after percutaneous delivery improved considerably when the transoral approach was used. In spite of its greater complexity, the transoral approach is probably more effective than the percutaneous route. We describe a curved device for transoral injection that is composed of simple elements available at any health center.