Subungual exostosis is a variant of osteochondroma that appears as a pinkish nodule under the free end of the nail plate. It becomes symptomatic when large enough to disrupt the overlying nail on the digit or through mechanical irritation of the exostosis from physical activity. Appropriate workup of such a lesion is important, because many cases of subungual exostosis are initially misdiagnosed by a variety of specialists, including dermatologists. With the use of history and roentgenography, subungual exostosis can be effectively diagnosed or excluded. Appropriate treatment of subungual exostosis can be selected— surgical excision of the lesion with significant cure rates achieved. Although most cases of subungual exostosis are localized to the great toe, we describe a 32-year-old woman who developed a subungual exostosis on her right third toe. Appropriate diagnostic workup and surgical treatment of the right third-toe exostosis has resulted in complete relief of symptoms with no signs of recurrence 7 months after surgery. (J Am Acad Dermatol 2001;45:S200-1.)