CNC milling is widely used in the present manufacturing scenario to manufacture components with complex shapes and profiles with high geometrical accuracy. The main aim of the present work is to analyze the significance of milling parameters on cylindricity and perpendicularity of circular pockets in CNC milling operation while machining AISI 304H stainless steel. Spindle speed and feed rate have been considered as machining parameters. The experimentation plan is implemented under Taguchi's L9 orthogonal array. The performance characteristics such as cylindricity and perpendicularity of the circular pockets were also measured using CMM. Mathematical models are developed using response surface methodology (RSM) to develop relationship between the input parameters and output responses.