Objectives. To determine the effect of consumption of a lipid-based nutrient supplement (LNS) on hemoglobin levels, anemia and anthropometric indicators in children aged six to eleven months old in five districts in the province of Ambo in the region of Huanuco, Peru. Materials and methods. A pre-experimental, pre-post study was performed. The study population included children aged six to eleven months old in 19 health facilities in five districts with very high vulnerability to chronic malnutrition in the province of Ambo, Huanuco. Data from 147 children who received the lipid-based nutrient supplement (LNS) from six to eleven months old were obtained. Results. The mean hemoglobin significantly increased by 0.67 g/dL (p<0.05), the proportion of anemia dropped by 27 percentage points (p<0.001) and the mean z score for height/ age decreased by 0.12 (p<0.05). No significant differences for z scores of weight/age and weight/height at the end of the study were found. The LNS had an adherence greater than 90%, and less than 10% of children in the study reported discomfort during consumption. Conclusions. LNS supplementation achieved improved hemoglobin levels and reduced the prevalence of anemia in children under twelve months, which might constitute an effective alternative to prevent and control childhood anemia.