The enthalpies of solution (H-2BAR - H-2-degrees) of Triton X-100 in water and aqueous ethylene glycol solutions have been measured calorimetrically at different concentrations in pre-cmc and post-cmc regions at 298.15 and 308.15 K from which the enthalpies of micellization, DELTA-H(m), and the heat capacities of monomeric, DELTA-C(pmono), and micellar, DELTA-C(pmic), forms as well as the heat capacities of micellization, DELTA-C(pm), have been calculated. The results indicate that the ethylene glycol-hydrocarbon interactions are more favorable than water-hydrocarbon interactions.