While more than 80% of childhood asthmatics are allergic to one or more inhaled allergens, the role of inhaled allergens in the induction of wheeze in the first year of life is unknown. In a prospective birth-cohort study of 499 children of asthmatic/allergic parents from metropolitan Boston, we examined home allergen concentrations measured within the first 3 mo of life as predictors of repeated wheeze episodes in the first year of life. In multivariate analyses adjusting for maternal asthma and dog in the home, predictors of two or more wheeze episodes in the first year of life included maternal smoking during pregnancy (relative risk [RR] = 1.83; 95% confidence limit [CL]: 1.12, 3.00), lower respiratory illness in the first year of life (croup, bronchitis, bronchiolitis, or pneumonia) (RR = 2.25; 95% CL:1.58, 3.19), low birthweight (RR = 1.28, 95% confidence interval [CI]: 1.04, 1.58 for an interquartile difference), and Bla g 1 or 2 (cockroach) allergen level in the family room > 0.05 U/g dust (RR = 1.76; 95% CL: 1.20, 2.57). Cockroach allergen in the family room and repeated wheeze remained significant after adjustment for socioeconomic factors including race and income (RR = 1.63; 95% CL: 1.05, 2.55). It is unknown whether the association between cockroach and repeated wheeze in infancy represents a cockroach-related increased risk of bronchial inflammation through nonallergenic or allergenic mechanisms.