The ultrastructure of the epithelium of wounded guinea pig palate was studied. Twenty-four biopsies (animals) were used. Biopsies were taken 18, 48, 96, and 120 h after wounding. Essential changes in epithelial cell structure in response to wounding were as follows: microfilaments, suggested to represent actin-containing filaments, became evident in the cortical cytoplasmic zone. Microtubules prevailed in the peripheral cytoplasm. Tonofilament bundles assumed the character of short tufts or delicate bundles and the amount of non-bundled tonofilaments was increased. These observations suggest changes in the cytoskeletal/contractile system facilitating cell motility. The structure of lysosomal profiles indicates an enhanced phagocytic capability. Influence of fixation on preservation of non-membrane-bound organelles is suggested based on comparable morphometric data.