Background: Malnutrition is a serious public health problem affecting the growth and development of children which have detrimental effect in later adolescent and adult life. Although Malnutrition is multifaceted problem, Infant and young child feeding practices by mothers is crucial for optimum growth and development of the children Objectives: 1) To Assess the Infant and Young child feeding practices followed by the Mothers. 2) To study the influence of feeding practices on weight of Under 3 years children. Methodology: Cross-sectional study conducted in an urban slum of Hubli. 110 mother-child pairs recruited , where the child was between 7 months to 3 years of age. Employed a pre-structured questionnaire as tool and Child’s Anthropometry done. Data presented as percentages and proportions. Chi square test is applied to test association between Feeding practices and underweight, P value less than 0.05 considered as significant. Results: 22.7 % mothers had Breast fed within recommended time following delivery, prelacteal feeding practices observed in 47.3 % and 37.3% followed Exclusively Breast Feeding. However Timely Initiation of complementary foods was seen only in 34.5%. Breast feeding continued in 47.3 % beyond 6 months. 53.6 % & 86.4% didn’t satisfy the Minimum meal frequency and dietary diversity respectively. 50.9% of children were Normal, 49.09% were Underweight. Conclusions: Nearly 50% of the children under this study were underweight. Mothers who had not Exclusively Breast fed for 6 months, not continued Breast feeding beyond 6 months and inadequate meal frequency of the child were significantly associated with underweight of the children.