Background: Under five children constitute the most vulnerable segment and their nutritional status and mortality rate is a sensitive indicator of the community’s health and nutrition. Prevalence of underweight is 35.7%, wasting is 21% and stunting 38.4% in India and for Odisha, it is 34.4%, 20.4 % and 34.1% respectively. Health indices of slum children are worst among all urban groups and are even poorer than rural average. Severe PEM is often associated with infection contributing to high child mortality in underprivileged communities of slum dwellers. Objectives of present study were to find out prevalence of under nutrition and its severity among the study population and to identify socio-demographic factors associated with malnutrition.Methods: A community based cross-sectional study was conducted from October 2015 September2016 in urban slum area of Berhampur city. Data were collected from 300 mothers of children aged 6-59 months using pre-tested semi structured questionnaires and measuring weight, height and MUAC of the children. Analysis was done using spss version- 20, Chi-square values and proportions were calculated.Results: 69% of 300 children were having under nutrition in the form of underweight (55.3%), wasting (75%) and stunting (42%). Overlapping of different type of malnutrition was seen. Maximum number of underweight children belongs to age group 37-60 months (52.6%) followed by other two age groups. 21.3% were severely wasted and 20% were severely underweight. Factors found to be significantly associated with prevalence of malnutrition were maternal education, hygienic and feeding practices of mother.Conclusions: Malnutrition is widely prevalent among study population more than the state and national prevalence. With increasing age cumulative increase in prevalence of malnutrition is seen perhaps due to persistence and addition of causative factors. Maternal education, faulty feeding practice and hygienic practice are contributory factor of this high prevalence of disease.