This chapter describes the key methods and salient results of Thin-Layer Chromatography (TLC) analyses of the skin products of vertebrates, specifically tetrapods. The naturally sloughed epidermal sheets of lizards and snakes and the molted feathers of birds are routinely available and have abundant chemicals for TLC. Solvent partitioning is performed to remove impurities and unwanted compounds from skin extracts prior to TLC analysis. Column chromatography may be used to fractionate lipids into general compound classes prior to TLC separations. Sphingosines and phytosphingosines, intermediates in the synthesis of ceramides and glycosylce-ramides, have been resolved by TLC from the epidermis of mammals. Nonpolar lipids in the skin secretions of vertebrates, including sterols, free fatty acids, alcohols, ketones, steryl esters, wax esters, triacylglycerols, and hydrocarbons, are separated routinely on silica gel G plates. Squalene, a hydrocarbon precursor of cholesterol, has been isolated by TLC from the skin secretions of several mammals.