The paper deals with the influence of different types of WC-Co powder mixtures processed by SLM technology on the final properties of the prototype build. The powder mixtures used differed in the morphology of the powder particles, i.e. the shape, size and chemical composition of the individual powder particles. In total, two different types of WC-Co powder mixtures were used for the experiment. The study was focused on the evaluation of the effect of these powders and other parameters of SLM technology (applied energy) on the resulting properties of the prototype sample. The samples were subjected to metallographic analysis after their preparation. This analysis was performed using metallographic and scanning electron microscopes. The metallographic analysis was supplemented by analysing the phase composition of the prototype samples and the changes in their chemical composition. The experiments enabled us to compare the differences in the properties of the prototype samples, especially in terms of their porosity, structural changes, changes in chemical and phase composition. The information obtained in relation to the parameters of the technology and the powders provided us with interesting data. The diffusion of the elements, especially carbon, meant the eta phase was formed in all of the samples, which is considered to be an undesirable phase in cemented carbides. However, its volume varied depending on the type of powder and the processing conditions. The smallest amount was recorded for samples made from a powder mixture with a free bond between the binder particles and tungsten carbide grains.