In the Regional Hospital "Victor Lazarte Echegaray" of Trujillo, Perú, it was made a study in order to determine the frequency of the acanthosis nigricans, associate to cancer (malignant acanthosis nigricans), during january 1978 to october 1983, and a case was founded in a patient of 62 years old, who had advanced adenocarcinoma gastric of one year and a half of evolution. The dermatosis was manifested with the neoplasia, which corresponds to a generalized form, with hyperkeratosis palmo plantar, with whole loss of the axillary hair and only part of the pubic region, the mucous membranes were not affected. The patient survived 3 months after the diagnostic were made.