Calluses are a diffuse area of hyperkeratosis occurring as a normal physiological response to chronic, excessive pressure or friction on the skin. THey can be distinctive occupational stigmata when they occur on the hands. Herein we report the occurrence of calluses of the thumb in professional milkers as an occupational dermatosis. © 2008 Dermatology Online Journal. © 2008 Elsevier B.V., All rights reserved.