Abstract: This research investigates the heat transfer performance for a flat plate collector using CuO/Water and CuO/Ethylene Glycol (EG). The scheme work concentrates on the process of energy transformation from the collector to the working fluid. This was achieved by using water and EG as base working fluid then using nanofluids as working fluids with different tilt angle and different flow rate. The experiment was constructed and conducted for several days from the September in Karbala Region. The base test has experimented with flow rates at (1.5 and 2.5 L/min) with 0.6% volume fraction nanoparticles. The result shows that the maximum temperature difference between the outlet and inlet was at the tilt angle 25° is (26.8) for CuO/EG and (33.6) for CuO/Water at the flow rate 1.5 L/min. In addition, it found that the best tilt angle which gives maximum solar radiation was at tilt angle 25° for Karbala Region in Summer days by test this experimentally with different tilt angles (15, 25, 35, 45 and 55°).