The free amino acid development of Appenzeller, Emmentaler, Gruyere, Raclette, Sbrinz and Tilsiter cheese is described. During the first five months of cheese ripening, the total amount of the free amino acids increases by 140-290 mg kg(-1) per day. Gruyere shows the highest increase for 15 amino acids, Appenzeller for valine, methionine, phenylalanine and ornithine, Raclette for alpha- and gamma-amino butyric acid, Emmentaler for alanine and Sbrinz for arginine. High quality cheese shows higher relative amounts of aspartic acid, asparagine and arginine and lower relative amounts of glycine, alanine, valine, methionine and isoleucine. The significant differences for Emmentaler were reversed for asparagine, alanine and methionine