Malnutrition is a major health problem especially for HIV-infected children. There is a vicious circle between HIV infection and malnutrition. Approximately 980 children became infected with HIV and approximately 320 children died from AIDS related causes, mostly because of inadequate access to HIV prevention (WHO, 2020). The study aimed to assess the nutritional status of under- five children living with HIV/AIDS at the Tropical Diseases Teaching Hospital-Sudan 2021. Methodology: A descriptive cross sectional hospital base study conducted at Tropical Diseases Teaching Hospital. 88 HIV- infected children attending Tropical Diseases Teaching Hospital were selected as participants. Data were collected using designed interview questionnaire. Results: According to (MUAC) 36.5% of the HIV- infected children were severely malnourished, 26.9% were moderately malnourished. According to weight – for –Height 76.1% of the HIV- infected children were underweight. According to height – for – age 39.6% of the HIV- infected children were moderately and mild impairment. 47.7% of the HIV- infected children have diarrheal disease during the last month. HIV- infected children's mothers attending the Tropical Diseases Teaching Hospital received health counselling from Health care providers. HIV- infected children were facing nutritional complications such as malnutrition, oral problems, lack of appetite, growth retardation. Conclusion: More than half of HIV- infected children were malnourished, facing nutritional complications such as, oral problems, lack of appetite, diarrhoea, growth retardation that are impaired their immunity. Adequate nutrition cannot cure HIV infection, but it is an essential part of maintaining the immune system and physical activity and of achieving optimal quality of life. Recommendation: Special attention of nutritional requirements for HIV- infected children, increases of mother's awerance about the health problem impaired child immunity. Nutritional .......