Abstract Background: Malnutrition is a global issue with patterns and prevalence that vary significantly not only among different nations of the world but also in different region of a country. This study aimed to determine the factors related to malnutrition diseases among children under- five years at El-Obeid Specialized Pediatric Hospital, North Kordofan- Sudan from April 2021 to October 2023. Methodology: This is an institutional cross-sectional descriptive analytical study. 384 of under-five children aged 6-59 months who were selected using simple random sampling technique was implemented. Data collection was focused on anthropometric tests (MUAC) for children and using structured questionnaire for mothers of children. Data were entered and analyzed using the Statistical Package of Social Sciences (SPSS) version 23.0 and chi-square (X²-test). Result: The results indicated that (38.8%) of children had suffered from malnutrition, more than quarter (27.1%) of the families their monthly income affected by the COVID 19 pandemic. Third of mothers (30.5%) held cultural beliefs related to child feeding. 13.5% of the children were not vaccinated. (2.9%) of families use drinking water from uncovered storage containers. There is statistical significant correlation between the monthly incomes, diarrhea in last two weeks, vaccination status and malnutrition statuses (p-value = 0.000). Conclusion: Based on our findings, the study indicated that family income, COVID 19 pandemic, family size; immunization, cultural beliefs and diarrhea are important factors that associated with malnutrition among children. The study recommended that doing further studies and continuous health education program among mothers for preventing malnutrion.