Abstract: Objectives: (1) To find the extent of undernutrition among under-five children in terms of stunting, wasting and underweight and also by composite index of anthropometric failure (CIAF). (2) To investigate some socio-demographic risk factors of child undernutrition. Study Design: Cross-sectional. Methods: A total of 371 under-five children from 816 households selected by stratified multi-stage random sampling technique. Collected information included weight, height, age, gender, social background, total calorie availability in the family, standard of living Index etc. Nutritional status was assessed by WHO criterion and CIAF. Statistical tests like Normal test of proportions, Chi-square test, Kolomogrov-Smirnov one sample test. Analysis of Variance (ANOVA) technique, Tukey's test and Multivariate Logistic Regression Model were used. Results: Proportions of underweight, stunting and wasting were found respectively 49.1%, 40.7% and 14.6% respectively. Children belonging to slum area and of low standard of living index were at significantly higher risk of being underweight. Anthropometric failure was observed in 62.8% children. Mean TCA for urban area was significantly higher than those for rural and slum areas. There were 57.1% children (72.3% in slums 71.3% from low SLI category) who were from TCA deficient families. About seventy five percent families of low standard of living, total calorie availability was below RDI and 73.1% children belonging to these families were having anthropometric failure. TCA deficiency was significantly associated with both SLI and social background. Low standard of living comes out to be an important risk factor of anthropometric failure irrespective of social background Conclusions: Undernutrition among under-five children should also be assessed by using composite index of anthropometric failure in order to avoid overlapping of different subgroups formed on the basis of standard indices of stunting, wasting and underweight. Low SLI comes out to be a risk factor of child undernutrition irrespective of social background. Nutritional status of children can be improved through social development by raising standard of living of people.