The effects of two added electrolytes up to high concentrations, 0-4 M NaCl and 0-6.6 M LiCl, on the critical micellization concentration (cmc) of octyl glucoside (OG), a nonionic surfactant, in aqueous solution have been measured. The fluorescence probe 6-p-toluidino-2-naphthalene sulfonate was used to determine the cmc values. Log cmc values were found to vary linearly with the molar electrolyte concentration, C-S, up to the highest concentrations. A theoretical approach based on the salting-out of the monomeric chain, presented in 1965, has been expanded by incorporating an additional effect of added electrolytes on the interfacial tension of the micelle-water interface. A group additivity relationship for the salting-out of hydrocarbon chains, also proposed in 1965, has been shown to give a good account of the salting-out coefficients of some hydrocarbons, primary alcohols, and methyl esters of carboxylic acids of different chain lengths obtained from literature data. Salting-out coefficients for the octyl group of OG in NaCl and LiCl, calculated on this basis, significantly overestimated the effects of electrolytes on the cmc of OG. Electrolyte effects on the interfacial tension of the estimated surface areas of OG micelles where hydrocarbons are exposed to water were calculated based on literature data on the effects of NaCl and LiCl on the dodecane-water interfacial tension. When these latter effects were combined with the estimated salting-out of the chains, the electrolyte effects on the cmc of OG could be explained nearly quantitatively up to the highest C-S. The results of some earlier studies in the literature have been shown to be compatible with the approaches presented. For long-chain surfactants in concentrated brine associated with some petroleum-oil recovery operations, the salting-out effects may have pronounced influences on their activities and how they change with salt concentration.