Background: Complementary feeding is the introduction of semisolid or solid food in infant who is on breast feeding, when mother’s milk is no longer enough to meet the nutritional needs. Understanding the social beliefs, knowledge, attitude and practices about complementary feeding among mothers is an important step prior to designing an intervention strategy to prevent malnutrition in children. Aim of the study was to assess the knowledge, attitude and practices regarding complementary feeding among mothers and its effect on growth of the child.Methods: Prospective study including 500 mothers with children between 6 to 24 months of age in KIMS, from December 2014 to November 2015. Results: Mean age of knowledge regarding complementary feeding in mothers was 8.01 months. Most of the mothers 307/500 (61.4%) started complementary feeding because of insufficient milk, 183/500 (36.6%) mothers started complementary feeding as they felt the child required more milk, 30/500 (6%) mothers started complementary feeding as the child was sick and not drinking milk. There is significant positive correlation between age of complementary feeding and malnutrition in first 2 years of life.Conclusions: Mother’s knowledge regarding timing of complementary feeding is inadequate and practices are inappropriate. Majority of them are not aware of the current recommendations. It is essential to give accurate information and education about complementary feeding to prevent malnutrition and improve the health status of children.