Corrugated ducts have been employed in a number of engineering devices to enhance heat transfer. They have been successfully used in compact heat exchangers, resulting in a more economical use of space and material. The problem of internal heat generation in computers has been solved by incorporating corrugated wall-channels into their cooling system. Heat transfer in gas turbines, which is often enhanced by turbulence promoters and jet impingement, may also be improved by installing corrugation in their internal cooling passages with an optimum spacing. An experimental investigation of natural convection heat transfer from corrugated inclined surface by constant heat-flux has been studied in this thesis. Experiments were done for two different amplitude-wavelength ratio of ?=0.18 and 0.257. Three different heat fluxes i.e. 6W, 7W, and 8W were applied on the plate which is 550mm long x 86mm wide. The experiments were done for the angle of inclinations: 0°, 30°, 45°, 55°, 60°, and 90° which are measured from vertical surface. The results show that by increasing the angle of inclination from ? =0° to ?=60° the wavelength of the local heat transfer coefficient variation is half of that of the wavy surface while for ? =65° to ? =90° the wavelength of the local heat transfer coefficient variation is the same as that of the wavy surface. The local heat transfer coefficient is an increasing function of heat flux value. The total heat transfer coefficient on the wavy surface is greater than that of the flat plate with the same projected area. The total heat transfer coefficient increase as the amplitude-wavelength ratio increases. This is due to the increase in the heat transfer area.