A recently developed thin-layer electrophoretic method has been applied to the determination of biomass degradation products comprising mono-, oligo- and polysaccharides and their derivatives as well as phenolic compounds. The separation was carried out using 0.3 M aqueous borate solution as the buffer and silanized silica gel as the support, the surface of the latter being covered with a thin film of octanol-1. For visualization of the carbohydrates, specific sulphuric acid-containing naphthoresorcinol and orcinol reagents were applied. The mobility of hydrolyzed products is determined by the number and position of their reactive sites and, to a less extent, by the size of their molecule. The good separations obtained confirm this method as an alternative to the commonly utilized chromatographic procedures.