Food irradiation has been steadily increased in many countries concomitantly with increasing international trades and concerns about naturally occurring harmful contaminants of food. Although, irradiation provides an excellent safeguard for the consumer by destroying harmful bacteria, it would be necessary to investigate nutritional adequacy of irradiated foods with a special emphasis on such foods as red pepper powders, cold-water fishes (mackerel), sesame seeds that are widely consumed in Korea. These food items are of special concern due to the fact that most of them are imported and that several nutrients contained in them are sensitively reacting to irradiation. We observed changes in the antioxidant nutrients contents, such as vitamin A, $eta$-carotene, vitamin C and total phenol, and also vitamin B$_1$ in the foods that were irradiated at different dose levels. The nutrients contents in red pepper were respectively 98.6% and 92.3％ for total phenol, and 97.8% and 94.5% for $eta$-carotene, right after irradiation at the dose of 10 and 20 kGy. The vitamin C contents decreased with irradiation doses up to 76.4% (10 kGy) and 68.5% (20 kGy) and B$_1$ contents decreased to 54.9% and 80.7% of non irradiated red pepper. When the mackerel was irradiated at the applied dose of 3 and 7 kGy, total phenol concentration of the irradiated fish was respectively 91.3% and 94.2% of non irradiated fish. The amounts of vitamin A were 82.6% (3 kGy) and 78.0% (7 kGy) of unirradiated sample and vitamin B$_1$ contents reduced to 30.5% and 51.5%. $alpha$-Tocopherol content was 33.9% of the non-irradiated one when it was irradiated at 7 kGy. Vitamin A and ${gamma}$-tocopherol contents in sesame seeds linearly decreased with the applied doses (5 and 10 kGy) Vitamin A contents decreased up to 87.8% (5 kGy) and 82.9% (10 kGy) and that of ${gamma}$-tocopherol were 72.4% and 66.5% of the unirradiated sample.