The lipid pattern and the fatty acid composition of human oral epithelium were studied qualitatively and quantitatively with the aid of thin-layer chromatography and gas-liquid chromatography. The material studied consisted of scrapings from the mucosa of the hard palate of nine cadavers and of three volunteers. Two methods for collecting the material were used: A) the epithelium was isolated by the removal of subepithelial connective tissue from the connective tissue side and B) the epithelium from the epithelial side was carefully scraped off. The lipid pattern of the epithelium was dominated by cholesterol (25 mol %) and phosphoglycerides (total 45 mol %), while triglycerides and free fatty acids constituted 10-15 mol % each. The fatty acid compostitions of the lipids were remarkably similar to each other, although the specific characteristics of each individual lipid were still noticeable. All lipids showed a large proportion of linoleic acid and a relatively small proportion of other polyunsatured fatty acids. In several respects the lipid pattern and the fatty acid composition of the epithelium were similar to those found in other ectodermal tissues, but they exhibited a number of differences from the corresponding pattern of the mesenchymal connective tissue.