The performance of Joule-Thomson refrigerators operating with mixed refrigerants depends on the composition of mixtures as well as the hardware employed. The role of mixture composition on the overall performance of the system has been well addressed in the open literature. What is not well known is the role of mixture composition on the performance of individual components such as the compressor, heat exchanger, etc. The adiabatic efficiency of a single stage Joule-Thomson refrigerator compressor was measured with thirty different nitrogen-hydrocarbon and neon-nitrogen-hydrocarbon mixtures. Our results show that the adiabatic efficiency of the compressor is independent of the mixture composition in the range of pressure ratios tested. © 2013 Elsevier Ltd and IIR. All rights reserved.