The Ruiz-Mora procedure has been advocated for the correction of hammertoe deformities and congenital overlapping of the fifth toe, primarily on empirical grounds. This is a review of forty-one such procedures in which the operation was used for correction of a hammertoe deformity of the fifth toe with a painful corn overlying the proximal interphalangeal joint. Twenty-two patients with thirty-one procedures were followed for an average of 3.5 years. All of the patients had complete relief of symptoms and correction of deformity. However, in 23 per cent of the patients a painful prominent head of the fifth metartarsal or a bunionette developed, and in 32 per cent a hammertoe deformity of the adjacent fourth toe developed with a painful corn either over the proximal interphalangeal joint or on the tip of the fourth toe. These problems seem to be related to excessive shortening of the the fifth toe. Less bone resection (resection of only the head and neck of the proximal phalanx) might be preferable and might not lead to these complications.