Nano fluids have high heat transfer potential, increased thermal properties in comparison with conventional working fluids which increases the Co-efficient of performance of the refrigeration system. The Present paper experiments are conducted on Vapour compression refrigeration system with R-134a as pure refrigerant and combination of Cuo-R134a as a Nano-refrigerant. Nano fluids have high heat transfer potential, increase thermal properties of conventional working fluids which increase the Co-efficient of performance of the refrigeration system. In this study the comparison of COP and power consumption of pure refrigerant R-134 and 1.6% concentrated Nano-refrigerant Cuo-R134a is investigated experimentally. Nano refrigerants are prepared by dispersing the Nano-particles of Copper oxides in base refrigerant R134a and are prepared in ultra Sonicator processor. In this experiment there is an increase of 16.66% of COP and 13.79% decrease in power consumption by using Nano-refrigerant comparing to pure refrigerant.