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Abstract  Studies were made on the stability of NaOCl at 40°C in the presence of sodium alkanesulfonate or alkylarenesulfonate anionic surfactants, and in the presence of a nonionic surfactant,N-octylpyrrolidinone. The results were compared with NaOCl stability in the absence of additives and in the presence of nonsurfactant short-chain sodium alkylbenzenesulfonates. The data indicated that the rate of NaOCl loss is greatly dependent upon the pH of the solution, even at alkaline pHs. At initial pHs below 11, in the absence of additive, there is significant disproportionation of OCl^− to ClO ₃ ^− , accompanied by decrease in the pH of the solution, within a period of several days. Even at an initial pH of 11.3, in the presence of the surfactants investigated, there is significant disproportionation of OCl^− and decrease in the pH of the solution in the first several days. When the initial pH of the solution is 13.5, there is no significant decrease in pH of the solution for at least two months in the presence of the surfactants studied. NaOCl stability in the presence of surfactant decreases in the order: sodium linear alkanesulfonate > sodium linear alkyldiphenylethersulfonate > sodium linear alkylbenzenesulfonate >>N-octylpyrrolidinone. Stability was greater in the presence of linear alkylarenesulfonates than in the presence of branched alkylarenesulfonates. It is suggested that the differences in stability observed are due to the greater ease of oxidation of tertiary carbon atoms compared to primary or secondary atoms.