In developing countries, protein-energy malnutrition causes 60% of deaths in children < 5 years of age. To evaluate the effect of a ready-to-use supplementary food (RUSF) on moderate acute malnutrition (MAM) in preschool children. Clinical trial that included 155 children with MAM (weight/height Z-score > -3 and ≤ -2). Each child received RUSF in the form of biscuits, four per day (250 kcal), for 12 months. The tutor received education on nutrition, health and hygiene. Recovery (weight/height Z-score > -2) at four, six, and 12 months was assessed using intent-to-treat (ITT) and per protocol (PP) analyses. Changes in chronic malnutrition were also analyzed. In the first semester, adequate RUSF consumption was observed in 61% of the children, and in 42% in the second semester. In the ITT analysis, 78% were identified to have recovered, with 38% reaching normal nutritional values; in the PP analysis, > 90% recovered and > 40% reached normal values. Recovery from chronic malnutrition was also observed. The consumption of RUSF and an educational program reduced MAM.