We tested to use several compositions of a four�| component�|mixture R32�^125�^134a�^600 as a refrigerant for replaclng R22 in refrigeration system of refrigerated warehouses�DR32�CR125�Cand R134a are hydrofluorocafbons and R600 is normalbutane�DThe refrigeration system designed for R22 can be used without any Change or with very minor change�DBy usig appropriate composition of the four�|component refrigerant�Cexisting refrigeration system can provide best performance because the adjusted properties of the refrigerant can somewhat compensate for the individual hardware problems. Practical operation test was done by using a refrigeration system of nominal cooling capacity of 30.2kW with a 22kW two-Stage compressor Which equipped for an 858m³refrigerated warehouse maintaining at�|30�Ž�D The pressure condition and the coeffcient of performance of R32�^125�^134a�^600 are similar to R22 from a theoretical viewpoint�DThe power consumption of R32�^125�^134a�^600 was small enough or not to be worse than that of R22�CWhich was confirmed from the actual test results�D