In ten patients a study of skin grafts and of the changes that occurred in the donor area was carried out: the primary retraction of the grafts in relation to their thickness was determined as well as the distension of the donor area of the graft after the excision of the same and comparison of it's thickness with that of the residual skin. The average thickness of the grafts was 318.0 micra, which corresponded to 20% of the donor skin. The primary retraction was 17.6%. The mean thickness of the residual skin at the donor area was 1,287.0 micra or 85.2% of the mean thickness of the reticular derma: the distension of the donor skin area after the removal of the graft corresponded to 2.1% of the original size.