The objective of this study was to determine the best irradiation markers in irradiated meat. Raw and cooked beef loins, pork loins and chicken thighs were irradiated at 0 or 5 kGy. The amounts of hydrocarbons, 2-alkylcyclobutanones, and sulfur volatiles were determined after 0 and 6 months of frozen storage. Two hydrocarbons (8-heptadecene (C17:1) and 6,9-heptadecadiene (C17:2)) and two 2- alkylcyclobutanones (2-dodecylcyclobutanone (DCB) and 2-tetradecylcyclobutanone (TCB)) were detected only in irradiated raw and cooked meats. Although pre-cooked irradiated meats produced more hydrocarbons and 2- alkylcyclobutanones than the irradiated cooked ones, the amounts of individual hydrocarbons and 2- alkylcyclobutanones, such as 8-heptadecene, 6,9- heptadecadiene, DCB, and TCB, were sufficient enough to identify whether the meat was irradiated or not. Dimethyl disulfide and dimethyl trisulfide were detected only in irradiated meats, but dimethyl trisulfide disappeared after 6 months of frozen storage under oxygen permeable packaging conditions. This indicated that only dimethyl disulfide could be used as an irradiation marker for the meat stored in frozen conditions for a long time.