The growing interest in nonazeotropic refrigerant mixtures for heat pumps and appliances has led to the need for a method of analyzing the refrigeration-cycle properties of such mixtures. Thermodynamic property tables are not sufficient, because they give no information about the two-phase region, where temperature and vapor and liquid compositions are not constant at constant pressure. This paper describes the computer program CYCLE, which can perform thermodynamic property calculations for subcooled, two-phase and superheaterd nonazeootropic mixtures and can analyze a simple refrigerating cycle.