Background: Andean pseudocereals are of great importance due to their good nutritional content and health effects. The effects of pseucereal consumption on body composition were compared in a murinometric model. Methodology: A randomized experimental study was carried out in 15 male Sprague-Dawley rats with an initial age range of 27 to 30 days old. The murinometric variables of weight (g) and total length (cm) were evaluated. Body composition (BC) was determined by regression equations, and fat mass (FM) and fat-free mass (FFM) were calculated. Three study groups were formed. The control group (CG) without protein intake, experimental group 1 (EG1) with casein protein supplement, and experimental group 2 (EG2) with protein supplement based on quinoa and ca & ntilde;ihua extracts. Results: Significant differences were verified between the preand post-test in the three study groups. In the CG, the values decreased 3.5g of FFM and 3.6g of FM (p<0.003), in EG1, FFM increased by 20.2g (p<0.001) and FM by 22g (p<0.001). In EG2, it increased FFM by 24g (p<0.001) and 26g in FM (p<0.001). When compared between post-tests, there were no significant differences between EG1 and EG2 (p= 0.07 and 0.09) in FM and FFM, however, there were significant differences between EG1 and EG2 with CG in FFM (p=0.000) and FM (p=0.000). Conclusions: Supplementation with pseudocereals (quinoa and ca & ntilde;ihua) and casein for 21 days produced significant increases in fat mass and fat-free mass in experimental animals (Sprague-Dawley rats). Consequently, the intake of Andean pseudocereals could improve body composition, presenting a great potential for application in the food industry.