A series of 31 operations on 27 patients for correction of the spastic thumb-in-palm deformity is reported. 19 patients were followed four years or longer post-operatively; the remainder have been followed for at least one year. In approximately 70 per cent of the operations, supplementary procedures were performed on the hand or forearm, as the deformity is usually only one facet of a complex spastic disability of the upper extremity. The surgical technique and illustrative cases are presented. Augmentation of a markedly weak extensor-abductor motor function is necessary, otherwise the spastic thumb-in-palm deformity will recur, as in two cases in the present series which required a second operation. The remainder of the patients were classified as improved, indicating that the thumb was no longer clenched in the palm, could be used in gross grasping activities, and the hand had become more useful. In no instance did the spastic hand become the primary functioning hand post-operatively.