The aim of this study was to evaluate the physical characteristics, such as expansion index, apparent density, porosity, texture and crunch, as well as general acceptability of extruded snacks based on purple corn (Zea mays L.), quinoa (Chenopodium quinoa W.) and kiwicha (Amaranthus caudatus L.). A simplex mixture design with an extended centroid was used, with the components: purple corn (M: 0.0 -100%), quinoa (Q: 0.0 - 100%) and kiwicha (K: 0.0 - 100%), with which obtained ten formulations. The results indicate that the M:Q:K ratio significantly affected the expansion index, bulk density, porosity, texture, crunch and general acceptability values. Treatment T9 (M: 17%, Q: 67%, K: 17%), presented the highest general acceptability with a mean of 7.59 and a mode of 9 (I really like it).