Surface tension studies of lithium soap solutions confirm that CMC values depend upon the composition of the solvent mixtures and are found to decrease with increasing chain length of the soap anion. In regards to chain length of the soap the CMC values follow the order : laurate < caprate. The results of the surface tensions have been explained on the basis of Szyszkowski’s empirical equation and it is observed that the values X, Y and (-X ln Y) lead to the confirmation of the fact that the change in the behaviour of the soap takes place at 40% methanol concentration whereas this consistency disappears above this concentration. The plots of the parachor against the mole fraction of the soap are characterized by an intersection of two straight lines at the CMC of the soap. Hammic and Andrew’s equation has been successfully applied to explain the behaviour of soap in benzene-methanol mixtures.