Different alternatives have been applied in order to substitute fat in food formulations, partially or completely, with ingredients such as carbohydrates, fibers and oleogels. In this sense, the application of solid lipid microparticles containing encapsulated polyunsaturated fatty acids, such as omega-3 (α linolenic acid) and omega-6 (linoleic acid), as fat replacers is an alternative yet to be evaluated. For that, three formulations of cookies were produced: control cookies (C) and cookies with partial replacement of margarine in 15% (M15) and 30% (M30) by lipid solid microparticles of carnauba wax containing encapsulated chia oil. Solid lipid microparticles were produced via hot homogenization with carnauba wax as encapsulatin material and sodium caseinate as surfactant for chia oil (rich in mega 3 and omega 6) encapsulation. Both, microparticles and the produced cookies, had their microstructure evaluated by Scanning Electron Microscopy showing that the sample M30 presented a thick layer around the starch granules, probably formed by melted microparticles. In cookies dough texture evaluation, a significant difference (p<0.05) was detected in hardness with higher value for control. Elasticity and resilience parameters of the samples containing the microparticles were significantly higher (p<0.05) than control sample. Regarding to color results, the cookies produced did not present significant difference (p>0.05) in relation to the luminosity. Finally, with the thermal characteristics evaluated by Differential Scanning Calorimetry, it was possible to observe that the microparticle sample had an endothermic peak at 83°C and cookies samples M15 and M30 presented the same peak displaced to 80°C. The intensity of such peaks was proportional to the amount of microparticles in the sample. Furthermore, food acceptability test (texture, flavor, appearance, odor and overall acceptance) showed that control sample scores ranged from 7 to 7.4, M15 sample scores from 6.6 to 6.8 and M30 samples scores from 6.2 to 6.5.