In the present work, theoretical and experimental investigation have been carried out with two hydrocarbon refrigerant mixtures as a possible alternatives to R134a. Theoretical performance of an ideal vapor compression refrigeration cycle using R290/R600 and R290/R600a was studied and the results were compared with those of R134a. The performance of the hydrocarbon mixtures of R290/R600 and R290/R600a were experimentally investigated as a drop-in alternatives to replace R134a in 297 liter domestic refrigerator designed to work with R134a. The results showed a lower freezer air temperature, lower cabinet air temperature, lower discharge temperature, higher coefficient of performance, lower pressure ratio and lower electrical power by about 3.2°C, 2.3°C, 3.1°C, 4.9%, 7% and 9.4%, respectively, for R290/R600 (60/40) % with 60g mass charge and 50% longer capillary tube compared with those of R134a with 120g mass charge.