The liquid-vapor and solld-llquid-vapor equilibria of the binary systems ethylene-n-elcosane and ethylene-n-dotrlacontane are studied, with particular attention being paid to the critical end points of the n-paraffin-rich branches of the S-L-V loci. Pressure, temperature, liquid-phase composition, and molar volume are reported. These data are discussed In comparison with existing ethylene-hydrocarbon phase equilibria data, taken by us and other investigators, from both a systematic and correlational viewpoint.