The surfaces of gram-positive bacteria, gram-negative bacteria, and acid-fast bacteria are discussed. The polysaccharides, acidic polymers, and proteins on the surface of gram-positive bacteria are detailed. The lipomannan, acidic polymers, and porin-like proteins in the cell envelope of mycobacteria are presented. The chemistry and synthesis of lipopolysaccharides, lipoproteins, and porins in the outer membrane of gram-negative bacteria are discussed. Attention is also given to cell surface-associated clumping and to resistance of surface molecules to digestion by enzymes.