Introduction: Under-nutrition contributes to more than one-third of all deaths in children. It does this by diminishing children’s immunity and making illness more dangerous. The primary aim of the study is to assess the nutritional status of children aged from 0 to 14 years in a slum area of Kolkata and secondary aim is to determine the prevalence of under-nutrition and its association with various risk factors among the study population. Materials and Methods: Community-based cross-sectional analytical study was carried out in urban slum of Chetla, Kolkata involving children of age group (0-14 years) from February to May 2012. All children (120) were examined clinically; their anthropometric measurements such as weight, height, mid upper arm circumference (MUAC) were taken using the standard operating procedures, after obtaining verbal consent from their parents with the help of a predesigned and pre-tested schedule. The anthropometric data was analyzed using World Health Organization Anthro and Anthro Plus Softwares. Results: The overall prevalence of under-nutrition among the study population was found to be 54 (45%). Among infants 9 (25%) were underweight, 3 (8.3%) were stunted, 22 (61.1%) were wasted and 23 (63.9%) showed thinness. Among 1-5 years aged children, 18 (30.5%) were underweight, 17 (28.8%) were stunted, 17 (28.8%) were wasted, 12 (20.3%) had MUAC 12.5-13.5 cm and 17 (28.8%) showed thinness. Among 5-14 years aged children, 11 (44%) were underweight, 10 (40%) were stunted and 12 (48%) showed thinness. Conclusion: The nutritional status of children in Chetla slum is not satisfactory in spite of proper immunization coverage and institutional deliveries. Special emphasis should be given for promotion of nutritional education to the mothers.