The fungal cell wall is a dynamic structure that protects the cell from changes in osmotic pressure and other environmental stresses. The cell wall has been shown to be primarily composed of chitin, glucans, mannans and glycoproteins. as revealed through mutational analyses, are discussed. There is strong evidence that the chitin, glucans and glycoproteins are covalently cross-linked together and that the cross-linking is a dynamic process that occurs extracellularly.