Raw and cooked beef and pork loins were irradiated at 0 or 5 25 kGy. The radiation induced marker compounds, such as hydrocarbons, 2-alkylcyclobutanones and sulfur volatiles, were determined after 0 and 6 months of frozen storage. Two hydrocarbons [8-heptadecene (C17:1), 6,9- heptadecadiene (C17:2)] and two 2-alkylcyclobutanones [2- dodecylcyclobutanone (DCB), 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 detect whether the meat was irradiated or not. Dimethyl disulfide and dimethyl trisulfide were also detected only in irradiated meats, but dimethyl trisulfide disappeared after 6 months of frozen storage under oxygen-permeable packaging conditions. The results indicated that 8- heptadecene, 6,9-heptadecadiene, DCB, TCB and dimethyl disulfide, even though they were decreased with storage, could be used as marker compounds for the detection of irradiated beef and pork regardless of cooking under the frozen conditions for 6 months.