Introduction: Iron deficiency anemia in children from 6 to 35 months is a severe public health issue. Objective: to determine the prevalence of anemia level and related factors in children under three years applying multicausal model in Peruvian population. Materials and methods: To explanatory level research was carried out applying a secondary analysis with data found in the database of the 2019 Demographic and Family Health Survey. The main variable was the level of anemia in which Hemocue® test was used. Weighted values, frequencies, percentages, goodness-of-fit, and an ordinal regression model were taken into consideration. Results: 40.20% of children under three years old presented anemia. Factors as presence of diarrhea (OR = 1.30), 12 months of life (OR: 3.33), not starting prenatal control (OR: 1.19), male gender (OR: 1.25), mother with anemia (OR: 1.75), mothers who are 15 to 24 (OR: 1.94), water well as a source of water (OR: 1.53), Aymara as mother tongue (OR: 2.31) were associated with anemia level. Conclusions: Among the risk factors associated with anemia according to the multicausal model, diarrhea in the last two weeks is a determinant factor, among the underlying factors are the child's age, source of drinking water, prenatal care, anemia and the woman's age. In addition, the protective factors correspond to breastfeeding for some time and the highest wealth quintile.