Abstract: 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, socio-economic, 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.