<title>Abstract</title> <bold>Background:</bold> Malnutrition affects millions of children worldwide, despite the Sustainable Development Goals, in the year 2022, Colombia faced serious food shortages and malnutrition, especially among children under 5 years of age. According to the National Institute of Health (INS), during that year 308 children under 5 years of age died due to malnutrition and related problems. Considering this situation, it can be observed that malnutrition increases the risk of suffering from respiratory diseases. Among these diseases is acute bronchiolitis, a viral infection that mainly affects infants and is located in the lower respiratory tract. The objective of this research is oriented to answer: What is the prevalence of acute malnutrition in patients older than 30 days and equal or younger than two years old hospitalized with bronchiolitis in the hospitalization service of Hospital Universitario Santa Clara in the months between February and July 2022? <bold>Methodology:</bold> Cross-sectional study or prevalence study, taking as study population, patients older than 30 days and younger than 2 years of age of both sexes requiring hospital management due to bronchiolitis. <bold>Results:</bold> From February to July 2022, a total of 183 patients were admitted to the inpatient unit of Santa Clara University Hospital due to acute bronchiolitis. Of which only 120 met the inclusion criteria proposed in the present study. It was found that 0.8% of the sample was obese, 10% overweight, 10.8% at risk of overweight, 46.7% were in an age-appropriate weight range, 23.3% at risk of acute malnutrition, 5.0% in moderate acute malnutrition, and 3.3% in severe acute malnutrition. There was a significant positive correlation between the z-score at admission and discharge of patients (R = 0.7996, p < 0.001). <bold>Conclusions:</bold> With the development of this research work and the statistical comparisons, we concluded that those patients admitted to the hospitalization unit for acute bronchiolitis, their nutritional status at admission is very variable compared to their nutritional status at discharge, as evidenced by their z-score calculated from weight and height.
