The prevalence of disease-related undernutrition in hospitalized children has not decreased significantly in the last decades in Europe. A recent large multicentric European study reported a percentage of underweight children ranging across countries from 4.0% to 9.3%. Nutritional screening has been put forward as a strategy to detect and prevent undernutrition in hospitalized children. It allows timely implementation of adequate nutritional support and prevents further nutritional deterioration of hospitalized children. In this article, a hands-on practical guideline for the implementation of a nutritional care program in hospitalized children is provided. The difference between nutritional status (anthropometry with or without additional technical investigations) at admission and nutritional risk (the risk of the need for a nutritional intervention or the risk for nutritional deterioration during hospital stay) is the focus of this article. Based on the quality control circle principle of Deming, a nutritional care algorithm, with detailed instructions specific for the pediatric population was developed and implementation in daily practice is proposed. Further research is required to prove the applicability and the merit of this algorithm. It can, however, serve as a basis to provide European or even wider guidelines.