The utilization of agro-industrial by-products and andean cereals in the elaboration of functional foods is evidenced in current research. Cereal bars stand out as fast foods with high nutritional value. The objective of the research was to formulate cereal bars counting as ingredients of oat bran study, pineapple peel powder and quinoa flakes; with adequate values of protein, firmness, sensory acceptance, dietary fiber and phenolic compounds. A simplex mix design with expanded centroid with a working range of 0 – 31,34% was applied. A significant effect of oat bran, pineapple peel powder and quinoa flakes was found on the response variables. The appropriate model to represent the behavior of the response variables was selected considering the values of p 0,80 and lack of fit > 0,05; being the cubic special model the one that better adjusted the data for protein and general acceptability; while for dietary fiber it was the quadratic model. It was determined that the optimal treatment was constituted by 4,12% oat bran; 10,04% pineapple shell powder and 17,18% quinoa flakes, having a protein content (11,37%), dietary fiber (13,28%) and general acceptability (7,47 points) which is equivalent to a very good perception.