A cross-sectional prospective study was performed to assess knowledge and attitude toward breastfeeding among mothers in a tertiary hospital in Malaysia and its influence on their breastfeeding practices. Two hundred thirteen women who had delivered healthy babies at term were enrolled. A structured questionnaire containing demographic data and the Iowa Infant Feeding Attitude Score were used, followed by a telephone interview after 8 weeks to determine the feeding outcome. Women of Malay ethnicity with higher education level who had received breastfeeding counseling had a significantly more favorable attitude toward breastfeeding. Ethnicity was found to be a significant determinant in the success of breastfeeding, whereas returning to work was a major reason for discontinuing breastfeeding. In ensuring a successful breastfeeding practice, apart from knowledge and attitude, issues surrounding culture and traditions as well as improving deliverance of readily available support should be addressed.