Cowden's disease is one of the rare genodermatoses. The most characteristic findings in this disease are cutaneous and oral lesions that are widespread papillomas and verrucous papules. On the palms the lesions are keratoses. Aside from these findings, this syndrome complex is sooner or later associated with various internal abnormalities involving the mammary, thyroid, gastrointestinal, reproductive and skeletal systems. In the 28 reported cases, 13 cancers have been found, most of the breasts. Because of the characteristic cutaneous and oral lesions, it is possible to recognize this disease early and then to follow afflicted patients closely for the possibility of development of cancers or other abnormalities of other organs.