The surface chemical composition of top fermenting brewing yeastSaccharomyces cerevisiaeMUCL 38475 was determined by XPS. The sample was prepared by washing the harvested cells in distilled water, freezing the suspension in liquid nitrogen, freeze drying, filling a trough with the powder and pressing gently. The yeast surface is mainly composed of carbon, oxygen, and nitrogen. Phosphorus and potassium were found as minor elements. The C 1s, O 1s, and N 1speaks were broken down into components which were assigned to chemical functions on the basis of analysis of sugar derivatives and homopeptides. The XPS analysis of brewing yeasts relates the surface chemical composition to physicochemical properties (electrical properties, hydrophobicity) and cell behavior (flocculation, flotation).