AbstractInfection and malnutrition and the effects of their interaction account for the majority of childhood deaths and chronic deficits in growth and development in Latin America. To promote child heath, the determinants of infection and malnutrition must be identified and cost‐effective interventions applied.Medical examinations of 988 children (age 2 weeks to 14 years) living at three altitudes in northem Chile revealed that 393 (40%) of the youngsters harbored one or more infections. When sorted by region and ethnicity, indigenous children of the highlands had infection rates 50 percent higher than those of Spanish descent living near the coast.An ecologic model was used as an organizing framework to illustrate the relationships among variables. Measurement of these variables revealed that health, age, and education of the mother were statistically significant predictors of child health, as were the child's nutrient intake and medical history. Traditional measurements of child health (weight, height, family wealth, and paternal occupation) did not differentiate between well and infected children.Policy implications are suggested for further validation. To focus on selected child health needs, such as feeding programs or immunization campaigns, without simultaneously attending to the environment from which the needs arise could be an inappropriate use of time, personnel, and mone