This paper presents experimental results of heat transfer and friction in a horizontal rectangular duct equipped with perforated wavy heat sink. The duct has a cross-sectional area of 0.06 x 0.36 m2 . The heat sink fin has many perforations and is bent to form a wavy shape. The wavy perforated fins are oriented and fixed perpendicular to the heat sink base. Many different heat sinks of the same width and height, with different fins structure have been investigated (fourteen heat sinks). The Reynolds number, Re, is ranged from 16500 to 22000. The dissipated power was 100 W (4630 W/m2 ). Experimental work is performed for fins divergence angles, 2α, from 15 to 45 degree, the diameter of the fins perforations, D, was 2, 3 and 4 mm, and the holes pitch is varied from 5 to 28 mm. The results showed that the average Nusselt number, Nu, increases with Re increasing and that for all the studied configurations, the most effective parameter on the Nu, was found to be fin divergence angle. Correlations are obtained for the average Nusselt number utilizing the present measurements within the investigated range of different parameters.