The performance of a hydrocarbon refrigerant, R-600a, as an alternative for R-12 has been evaluated in a 215 ℓ household auto-defrost refrigerator/freezer. A theoretical analysis was performed with NIST REFPROP, based on the ASHRAE refrigeration cycle and a series of tests with R-600a was conducted according to the Korea Standard (KS C 9305). All the tests were performed in the climate chamber of which the temperatures and relative humidities were maintained at 30±1°C and 75±5%, respectively. The test results showed that the energy efficiencies and the cooling speeds with R-600a were improved by 1–11% and 3–10%, respectively, compared to R-12.