Infections and malnutrition remain the main causes of infant mortality in developing countries. In protein-calorie malnutrition, immunologic responses are affected, which often facilitates infections. However, the presence of asthma and allergic rhinitis are not commonly recognized in malnourished individuals. The aim of this study was to evaluate serum IgE values in children with primary moderate protein-calorie malnutrition. METHODS The level of IgE in peripheral blood of 18 children between 2 and 4 old with moderate protein-calorie malnutrition and without associated parasitic infestation was compared with that of 15 well nourished children of similar age. IgE serum levels were measured by an immunoenzymatic method. RESULTS The median level of serum IgE in malnourished children was 69.30 ng/ml while the control group showed a mean level of 95.97 ng/ml. This difference was significant (p < 0.01). CONCLUSIONS Malnourished children show decreased serum IgE levels. This might be one of the adaptive mechanisms of malnutrition employed in an attempt to use energy and protein reserves for growth and other functions. Our results are coherent with the decrease in IgE mediated reactions in malnourished patients.