The effects of γ-radiation on myo-inositol in aqueous solution in the presence and absence of oxygen and in nitrous oxide have been studied. Although yields were variable, myo-2-inosose (2,4,6/3,5-pentahydroxycyclohexanone) has been shown to be the predominant primary product regardless of the conditions used, which indicates a strong steric influence on the reaction path. Other products varied with the conditions used, but idaric acid was always produced. Subsequent reactions were complex but ultimately led to carbon dioxide. Possible mechanisms for the primary reactions are discussed.