Aims: To assess the nutritional status and describe factors associated with the nutritional status of children under 5 years of age at the Pediatric Department of Hanoi Medical University Hospital. 

Methods: A cross-sectional study was conducted on 158 children under five years of age who attended the Pediatric Department for examination and treatment from December 2024 to April 2025. Data were analyzed using Jamovi software.

Nutritional status was classified according to the WHO 2006 Child Growth Standards using the WHO Anthro software. In this study, children with at least one of the three forms of undernutrition (underweight, stunting, or wasting) were classified as undernourished.

Results: This study observed that 7.6%, 7.0%, and 2.5% of the children were stunted, wasted, and underweight, respectively. The prevalence of overweight and obesity was 1.9%. Children aged 24–59 months had a 3 times higher risk of malnutrition than those under two years of age. Children with a birth weight <2,500 g had a 20.1 times higher risk of malnutrition than those with a birth weight ≥ 2,500 g (OR = 20.1; 95% CI: 1.99–202.7). In addition, children whose mothers ate less during pregnancy and those whose mothers gained less than 10 kg during pregnancy were at significantly higher risk of malnutrition (OR = 9.81; 95% CI: 1.98–48.40 and OR = 3.38; 95% CI: 1.33–8.59, respectively).

Conclusion: Malnutrition remains a concern among children under five years of age. Stunting is the most prevalent, followed by wasting and underweight. Factors associated with malnutrition among children under five years of age included child’s age, low birth weight, maternal nutrition during pregnancy and inadequate maternal gestational weight gain.