The aim of the study is to identify the Socio Economic and Environmental risk factors of protein energy malnutrition among children less than five years of age. Study group consists of all mother’s children (120) attending Omdurman Pediatrics Hospital (Sudan) and their children, 0-60 months of age, clinically diagnosed with protein energy malnutrition (Marasmus, Kwashiorkor and Mrasmic Kwashiorkor) during July to November 2011. A survey was conducted through questionnaires and personal interviews. From this study several risk factors were found to be associated with Protein Energy Malnutrition (PEM) including, low education level of the mother, number of children in the family, and age of the child. About 39.1% of the respondent had 5 – 6 children, 74.2% of the respondent had 1 -2 children in family less than 5 years. The higher the families size with the younger ages are more vulnerable to have PEM than those of older age. Also results revealed that PEM was more found in families of history of malnutrition in other sibling and younger age than others with statistically significant differences, 90% of the families earn up to 600 Sudanese Pounds per month. Statistically significant differences between practices of mothers were found regarding breast feeding, artificial feeding and additional and adult food. No statistically significant differences were found regarding incomplete vaccination, management of diarrhea, awareness of oral rehydration salt (ORS) packets and preparation of ORS and significant (P> 0. 05) differences were found in preparation of oral rehydration home-made solution. Health education to the mothers about proper feeding practices, breast feeding, artificial feeding and additional and adult food is recommended to prevent PEM. Increasing mother's awareness related to risk factors of PEM and how to manage the different infections among their children and encourage vaccination at the appropriate time is also recommended.