In mould manufacturing the most representative component is the cavity, which can represent up to 75% of the total cost of the tooling and can reach 40% of manufacture time. In regions with small sizes and area with difficulty access to the cutting tool with "common"size (>2mm).These areas have been machined by EDM which has a negative impact over the cost and time of manufacture of the mould cavity. Therefore, surveys are developed in order to reduce the use of EDM in industry; among the alternatives, the micromilling process, using high-frequency spindle together with cutting tools smaller than 1 mm of diameter in HSM machine has been emerging as an option for machining small regions in dies and moulds. This book contains the results of the comparison between EDM and micromilling process applied to the mould industry.Machining experiments were carried out on AISI P20 and AISI H13 steels. Residual stress on machined surface, surface finishing, SEM images, microstructure and microhardness and additionally, an analysis of time and cost of manufacturing were carried out. The milling time was approximately 5 times lower than EDM one and generated a savings of 46% in the manufacturing.