The ESR spectra of the flesh of a selection of unirradiated and γ-irradiated citrus fruits have been obtained. When dried, the flesh from unirradiated fruits gives rise to virtually no ESR spectrum. However, the flesh of irradiated fruits exhibit a strong spectrum with radiation induced features which show a high degree of reproducibility within the fruits examined. These features have been previously observed in spectra from the intact skin and skin components of irradiated citrus fruits. It is believed that this is the first time that radicals have been observed by ESR in the flesh of irradiated fruits.