Present work includes understanding the effects of various milling parameters such as spindle speed, feed rate, depth of cut and coolant flow on the surface roughness (Ra) of finished products. This book involves an experimental and theoretical analysis to predict Optimization of Surface Roughness in Milling using Taguchi's technique. Surface roughness is very important due to it is one of the most specified customer requirements and the major indicator of surface quality on machined parts is surface roughness. The surface roughness is mainly a result of various controllable or uncontrollable process parameters and it is harder to attain and track than physical dimensions are. Taguchi's technique is implemented to model the end milling process and predict the resulting surface roughness. Data is collected from CNC milling. Determination of the optimal cutting parameters (cutting conditions) such as the number of passes, depth of cut, speed, and feed is considered as a crucial stage of milling machining processes and especially in process planning. This is mainly due to the complex nature of optimization of machining operations.