Background: Aim of the study was to examine the under nutrition among infants aged one to twelve months. Also, find out the influence of infant feeding practices on baby weight by the first birthday. This was a prospective cohort study to collect the data by visiting the village health centres.Methods: This was a prospective cohort study of infants. We enlisted 157 new-born infants by a multi-cluster random sampling method representing the entire Primary Health Centre area. We obtained the written consent of mothers who participate in our study. These babies are followed up by periodic visits for a year. The data compiled, descriptive summary made, analysed with the Kolmogorov Smirnov test, chi-square test to infer statistical significance using SPSS 20.00 Software.Results: There were 157 babies (n) who met the inclusion criteria, Male 51%, female 49%, Birth order ≤2 are 85%, Gestational age ≥38 weeks are 85%, all the babies gained weight, however, only 73.9% of them weighed more than third percentile growth curve, at the first birthday. Among those babies who weighed less, 6% of babies too low weight, less active, while 20% is thin and active. A significant relationship is seen between the baby weight with feeding practices, Clinical Features, and lactation at a 5% level (p<0.05).Conclusions: The under nutrition has its origin in infancy. In our observation, 26.1% of babies remained undernourished by their first birthday. The main reasons for under nutrition is inadequate to breastfeed, an inherent lack of appetite, and imbalanced feeding practices.