Apparent molar volume and adiabatic compressibility properties of halothane and isoflurane in aqueous micelle solutions of hexadecyltrimethylammonium bromide (CTAB) and chloride (CTAC) have been studied as a function of surfactant concentration and temperature. Specific conductance measurements of the micellar systems in the presence and absence of the additive molecules were used to estimate the effect of the solubilized additives on the apparent degree of micelle dissociation. As well, H-1 T-1 relaxation and chemical shift studies of the micellized surfactant in the absence and presence of the additive were measured in an attempt to obtain complementary data regarding the solubilization sites of the additives in the micellar systems. The results show that the degree of micelle ionization, the extent of hydration of the counterions and of the head groups of the micellar systems, and the polarity of the anesthetic molecules play a role in the solubilization process. The inhalation anesthetics appear to be adsorbed in the head group region of the micelles, replacing water in this region in the case of the more hydrated micelles. Also, they penetrate to sites nearer to the alpha- and beta-methylene groups of the surfactant hydrocarbon chains when head group sites become saturated or the additive is less polar.