The reaction of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane DDT, with hydroxide ions (NaOH) was studied in cationic micellar aqueous solutions of tetradecyltrimethylammonium bromide, TTAB, and hexadecyltrimethylammonium bromide, CTAB, in the presence and in the absence of various added electrolytes (NaCl, NaF, NaBr, NaNO3, and Na2SO4). In the absence of added salt, the influence of the variations of the surfactant concentration as well as of the total hydroxide ions concentration on the observed rate constant values has been investigated. Kinetic data show that for low [NaOH], a phase separation model can explain the experimental results. However, as the hydroxide ions concentration increases, an additional pathway across the micellar boundary becomes important. When added electrolytes are present in the micellar reaction medium, variations in k(obs) depend on the nature of the anion of the salt, as well as on [salt](added). For a given added electrolyte concentration the observed trend was k(obs)(NaF) > k(obs)(NaCl) > k(obs)(Na2SO4) > k(obs)(NaBr) > k(obs)(NaNO3). This trend can be explained by considering the affinity of the different anions for the positive sites at the micellar surface, which is the factor controlling the hydroxide ion concentration present in the micellar pseudophase. The kinetic effects of the added electrolytes show that the ion-exchange equilibrium constants are similar for the CTAB and TTAB aqueous micellar solutions.