Low birthweight (LBW) is one of the primary causes of infant mortality. It shares 27% of infant mortality rate (IMR). The Indonesian Demographic and Health Survey in 2007 reported that the IMR was 34 deaths per 1,000 live births. As much as 30.3% of this rate was accounted by LBW. As such LBW is an important global public health issue. Countries arround the world have committed to overcome this problem. This study aimed to investigate the effects of maternal education, psychosocial stress, nutritional status at pregnancy, and family income, on birthweight.