In 1954, research was started on the effects of ionizing radiation on fresh fruits and vegetables. More information was needed because the claims then being made of long shelf lives for unrefrigerated irradiated commodities were biologically questionable. This article is a summary of 15 years work, and offers an evaluation of the commercial potential for irradiation of some major California commodities. Gamma rays from cobalt-60 were used in these tests, but the results would be comparable with other types of radiation; certainly, the commercial potential would not change. Only one California commodity, strawberries, showed promise for commercial application of radiation and even with this crop its use would depend on major changes in marketing conditions.