Surface roughness is one of the determinant factors that governs the quality of machined surfaces. This paper experimentally studied effects of machining parameters on the surface roughness (R_a) for end milling of AISI 1045 work piece using a TiAlN coated carbide milling cutter. Taguchi optimization method was used to determine the optimal level of three control factors, namely, the feed rate, the spindle speed and the depth of cut. Analysis of variance demonstrates that the feed rate is the most significant parameter and contributes 47% for surface roughness. Finally, the contour plots of these three parameters have been analysed to determine the optimal ranges of control factors.