Known as R134a refrigerant is in the class of refrigerants as uneconomic and having global warming potential. In the scope of study, determination the effect of R600a refrigerant which is known more environment friendly and economic alternative of R134a refrigerant on the cooling performance of the cooling machine was aimed. In this reason, effect of R134a and R600a refrigerants on the cooling performance of the cooling machine was experimentally studied. Experimentation setup was established with 70x70x50 cm dimensions cooling room and cooling unit. 100 gr refrigerant filled experimentation setup was operated at 28 degrees C and 35 degrees C ambient temperature in a period of time and according to the taken measurements cooling systems COP value was compared. As a result, using R600a refrigerant instead of R134a refrigerant, the cooling machine average COP value was increased 4%. This case demonstrates that R600a using cooling machine performs higher performance than R134a using cooling machine. Also, it was seen that a using coolant R134a cooled the space faster than a using coolant R600a in cooling machine.