RATIONALE: Allostatic load (AL), a novel measure of the physiologically dysregulated response of the body to stress, represents a biomarker of chronic stress exposure. OBJECTIVE: To determine whether pre-adolescent children with high AL are more susceptible to asthma as adolescents. METHODS AND MEASUREMENTS: This was a prospective evaluation of children recruited at age 7-10 in the nested case-control arm of the Study of Asthma, Genes and Environment (SAGE) and followed until ages 11-14. AL was measured using eight biomarkers: fasting glucose, total cholesterol, high density lipoprotein cholesterol, dehydroepiandrosterone sulphate, cortisol, systolic and diastolic blood pressure, and waist-to-hip ratio. AL, created from the sum of biomarkers in a high risk quartile, was related to prevalence and incidence asthma using logistic regression. RESULTS: Among 352 participants followed until 11-14 years, prevalent asthma was 4 times more likely in boys with high (>3) versus low (≤2) AL after adjusting for current asthma/atopy, age, ethnicity, parental history of asthma, and overweight status. Similar results were observed in the analysis of new-onset asthma in boys (adjusted OR: 4.35, 95% CI: 1.19-15.9). In girls, there were no associations between AL and asthma. In the analysis of a subset of biomarkers, combinations of total cholesterol, glucose, and cortisol were associated with similar or greater risk of asthma prevalence or onset in boys. CONCLUSION: AL and its biomarkers are associated with an increased likelihood of asthma in adolescent boys. The observed association between AL and asthma may be attributable to a combined subset of AL biomarkers.