This paper aims at determining the socioeconomic and demographic determinants related to Body Mass Index (BMI) for children under-five years in Sudan. This study uses the Sudan Multiple Indicator Cluster Survey (MICS) conducted in the year 2014. The survey was conducted by the Central Bureau of Statistics in cooperation with several national institutions. The objective of the study is to identify the factors of BMI for under-five children. The multinomial logistic regression model was adopted. Results revealed that the prevalence of underweight for infant’s under-five years was 86.3% for females and 85.3% for males, the proportion of the normal weight of infants under-five years of age for males is slightly higher than that of females; there is correlation amid geographic determinants; state, and BMI status. Also, there was a significant association between mother’s education and body mass index status and the wealth index and body mass index status. The variables place of residence and sex did not show a statistically significant relationship with body mass index status for the children under-five years of age in Sudan. In addition, the risk factors significantly associated with body mass were the state, child ever breastfeeds, sex, mother’s education, wealth index, and age in the month.