Severe malnutrition and very low weight were assessed as potential indicators for the classification of protein-energy malnutrition in the guidelines for the integrated management of childhood illness. For severe malnutrition, the authors examined 1202 children under age 5 years admitted to a Kenyan hospital for any association of the indicators with mortality within 1 month. Bipedal oedema indicating kwashiorkor, and the marasmus indicators of visible severe wasting and a weight-for-height (WFH) Z score of less than -3 were associated with a significantly increased risk of mortality. Very low weight-for-age (WFA) was not associated with an increased risk of mortality. Bipedal edema and visible severe wasting were chosen as indicators of severe malnutrition since first-level health facilities typically lack length-boards. Data for 1785 Kenyan outpatient children as well as survey data from Nepal, Bolivia, and Togo were used in assessing potential WFA thresholds for the very low weight classification. Use of a WFA threshold Z-score of less than -2 identified from 13% of children in Bolivia to 68% in Nepal who would in most settings burden health facilities. Among sick children in Kenya, a threshold WFA Z-score of less than -3 was 89-100% sensitive in detecting children with WFH Z-scores of less than -3 and, with an identification rate of 9%, would not overburden health clinics. Potential modifications include the use of a more restrictive cutoff in countries with high rates of stunting or the elimination of the WFA screen in order to focus efforts upon intervention for all children under the 2-year age cutoff.