A classification of limited hyperkeratoses (LH) was developed for practical use in out-patient surgical practice on the basis of literature data and personal studies and observations over 630 patients. Hyperkeratoses are classified according to the etiological sign (mechanical damage to the skin, diseases and deformities of the locomotor apparatus-neurotrophic, genetic, miscellaneous), clinical course (acute LH-soft corn, uncomplicated and infected and chronic LH-dry corn or callus, uncomplicated and complicated with suppuration, formation of fistula, malignization), according to shape (spherical, ellipsoid, cone-shaped), according to localization (hand and foot, unilateral, bilateral, combined, palm, finger, toe, interdigital), according to size (small, moderate, large), and according to number (solitary, multiple). The cause of the disease in 452 patients was the mechanical effect of poorly fitting shoes and trauma caused by various objects. In 19 patients LH occurred as the result of a pathological condition of the locomotor apparatus (exostosis, flexion contracture of the toes, amputation stump, etc.). In 70 cases LH was a consequence of diseases of the peripheral nervous system. There were rare causes in the remaining patients. Various methods of treatment are suggested, including the use of a laser scalpel, depending on the classification signs of the disease. Removal of the etiological factors is a very significant measure in the treatment and prevention of LH.