ABSTRACT The Devonian oil shale of Kentucky (Cleveland Member of the Ohio Shale) proves to be more susceptible to air oxidation than a high sulfur coal such as Western Kentucky No. 9, and much more susceptible than the Eocene Green River Formation shale of Colorado. The Mississippian oil shale (Sunbury Shale) is also readily air oxidized. Oxygen uptake per 100-grams organic carbon content over 10 hours at 30∗C taken from plots of oxygen uptake vs. time is as follows: Ohio Shale, 650 cc; Sunbury Shale, 200 cc; Green River Formation shale, 50 cc; Ky No. 9 coal, 40 cc. Special care in protecting samples from autoxidaion is required if good assays and analyses are to be obtained. The aging chacacteristics of eastern oil shales could potentially affect mining, transportation, crushing, screening, and stockpiling of feedstocks, particularly fines, for a commercial oil shale operation in Kentucky.