We evaluated the impact of socioeconomic and maternal conditions, treatment frequency and frequency of infections, parasites and anemia in the increment of height for age (H/A) in children (< 5 years) undergoing treatment at day-hospital at a Center for Recovery and Nutritional Education (n = 57). Upper respiratory infections were the most frequent disease with positive association with the severity of undernutrition (p = 0.035) and age at admission (p = 0.001). In multiple regression analysis, the severity of undernutrition, low hemoglobin level, family income and the low frequency at the service were predictors of increment in stature (p < 0.05). The findings show the importance of treatment in day hospitals for undernourished children.