Electrolytic conductance measurements for potassium alkyl xanthates (alkyl : methyl, ethyl, 2-propyl, butyl, and S-methyl-l-butyl) are reported at x(A) = 0.20, 0.40, 0.60, 0.80 dimethyl sulfoxide (A) + propylene carbonate (B) mixtures at 25 degrees C. The results are analyzed by the Fuoss conductance-concentration equation. Values of limiting molar conductance Lambda(0), association constant K-A, and cosphere diameter R are obtained, and an attempt is made to relate these parameters to the increasing size of the attached alkyl substituents in the xanthate anion.