Size effect is a phenomenon which can explain the difference of the behavior of a material in a manufacturing process in reduced scale, that is, the difference between the mechanics of cutting in micro and mesoscale. This phenomenon in micromilling deals principally with the decrease of the ratio undeformed chip thickness (tc) per cutting edge radius (re) and the microstructure of the workpiece. On a previous work, it was presented an experimental study on the influence of cutting parameters in micromilling of superduplex steel, considering only two levels of cutting speed and feed per tooth. The objective of the present work is to verify the influence of the size effect on the specific cutting pressure and on the surface integrity in the micromilling of this steel. The Design of Experiments used two levels of cutting speed and six levels of feed rate. The combined analysis of the results of both studies shows a higher influence of the feed rate on the non-linear increase of the specific cutting pressure and, consequently, on the roughness and burr formation.