The conductance behavior of potassium iodide, potassium perchlorate, silver perchlorate, silver picrate, sodium iodide, sodium tetraphenylboride, and tetrabutylammonium iodide has been studied in 20, 40, 60, and 80 mass % ethylene carbonate + water mixtures at 25 °C. The conductance data are treated on the basis of the Fuoss equation, and the limiting molar conductivity (Λo), association constant (K A), and cosphere diameter (R) are derived from the treatment. From the algebraic sum of the limiting molar conductivities of tetrabutylammonium iodide, sodium tetraphenylboride, and sodium iodide, the value of limiting molar conductivity of tetrabutylammonium tetraphenylboride reference electrolyte is calculated for the determination of the limiting ionic conductivity (λo) of the systems studied.