A generalized procedure is proposed for calculating the thermodynamic properties of pure organic compounds usable as working fluids in closed-cycle power systems and heat pumps. The method is based on a generalized equation of state obtained by reformulating the B. I. Lee and M. G. Kesler (1975) correlation and is compatible with sophisticated algorithms described in previously published work and developed for single fluids. The algorithms use auxiliary equations for calculating vapor pressure and specific volumes of the saturated liquid and vapor. The thermodynamic consistency of the procedure and its reliability in calculating the volumetric and derived thermodynamic properties is verified by carrying out systematic checks on a number of organic fluids with different volumetric behavior. The results confirm the suitability of the method for calculating direct and inverse thermodynamic cycles.