In six pigs from 7 months to 3 years of age the cleavage line pattern of the skin was examined in the whole body by a thick metal probe with a sharp conical point. Directionality of the cleavage lines was determined from the relationship of the line of the long axis of each physical structure. The cleavage lines of adult pigs were compared with those of young pigs (Wakuri, 1967). The cleavage lines of the ear, neck, trunk, and free extremities of appendage were quite similar in adult and young pigs. Those of the buccal, interscapular and sacral regions, umbilicus and scrotum showed slight differences. The most noticeable directional variability in cleavage lines appeared in the masticatory region, arms and legs of adult pigs. Cleavage lines were found to be transverse in arrangement in the masticatory region, auricular root, neck, trunk, tail and legs. They showed an annular pattern around the preputial orifice and in the arms and anogenital region.