Amino acid homopolymers were used to determine production of radiolytic volatiles by irradiation. Many new volatiles were generated, and the amounts of volatiles in amino acid homopolymers changed after irradiation. Each amino acid homopolymer group produced different odor characteristics, but the intensities of odor from all amino acid groups were weak, except for sulfur-containing amino acids. Sulfur-containing amino acids produced various sulfur compounds; the overall odor intensity of irradiated sulfur amino acids was very high and the odor characteristics of sulfur amino acids were similar to irradiation odor of meat. Our results indicated that the contribution of methionine to the irradiation odor would be far greater than that of cysteine.