The nutritional status of under five children is a sensitive indicator of a country’s health status as well as economic condition. This study investigated differential impact of some demographic, socioeconomic, environmental and health related factors on nutritional status among under five children in Bangladesh. The study used Bangladesh Demographic and Health Survey 1999-2000 (BDHS 1999-2000) data. Bivariate analysis and multivariate analysis (Cox’s linear logistic regression model) were used to identify the determinants of under-five malnutrition. The analyses revealed that 45 percent of the children under age five were suffering from chronic malnutrition, 10.5 percent were acutely malnourished and 48 percent had under-weight problem. The main contributing factors for under five malnutrition were found to be previous birth interval, size at birth, mother’s body mass index at birth and parent’s education.