Malnutrition remains one of the most common causes of morbidity and mortality among children throughout the world, this study aimed to identify children aged 6months to less than 5 years with malnutrition, mothers knowledge in Sumbawanga municipal. Health care professional have a responsibility to assist each children to provide education on health to their mothers, good appropriate of meals, treatment for malnutrition according to their needs and circumstances. The objective of this study is to identify malnutrition among children aged six months to less than five years. This cross-sectional survey will be conducted through questionnaire administered in mothers of Sumbawanga municipal. The study will be conducted in August 2019.