The conductometric studies of the solutions of samarium valerate and caproate in methanol and in a mixture of water and methanol in presence of electrolytes (uni-, bi- and tri-valent) and non-electrolytes were used to evaluate the critical micelle concentration (CMC) and the free energy change for the micellization process. The CMC was found to decrease with increasing ionic radii of counterions. The results suggest that these soaps behave as weak electrolytes in dilute solutions below the CMC.