OBJECTIVE This study aimed to determine the relationship between individual allergens with current wheezing and bronchial hyperresponsiveness (BHR) in schoolchildren from three chinese cities: Beijing, Guangzhou and Hong Kong. METHODS Community-based random samples of 10-yr-old schoolchildren from the 3 cities were recruited for study using the International Study of Asthma and Allergies in Childhood (ISAAC) Phase II protocol. The subjects were studied by parental questionnaires (n = 10,902), skin-prick tests (n = 3478), and methacholine challenge tests (n = 608). RESULTS The highest prevalence rates of wheezing in the past 12 months (Beijing, 3.8%; Guangzhou, 3.4%; Hong Kong, 5.8%) and atopy (Beijing, 23.9%; Guangzhou, 30.8%; Hong Kong, 41.2%, defined as having <or= 1 positive skin-prick tests,) were seen in schoolchildren from Hong Kong. The highest prevalence rates of BHR (Beijing, 33.2%; Guangzhou, 45.8%; Hong Kong, 30.7%) were seen in schoolchildren from Guangzhou. Multivariate-logistic regression analyses revealed that sensitization to Dermatophagoides pteronyssinus [odds ratio ((OR)) = 4.48; 95% confidence interval ((CI)); 3.02-6.66], cat ((OR) 2.85; 95% (CI) 1.24-6.50), Dermatophagoides farinae (DF) ((OR) 2.41, 95% (CI) 1.65-3.51) and Mixed grass pollen ((OR) 2.85, 95% (CI) 1.24-6.50) were significantly associate with current wheezing atopy ((OR) 1.29, 95% (CI) 0.74-2.24), was not an independent risk factor for current wheezing in children from any of the three cities. Furthermore, atopy ((OR) 2.53, 95% (CI) 1.93-6.97) were significantly associated with BHR. CONCLUSION The authors confirmed that sensitization to house dust mite and cat was significantly associated with current wheezing and bronchial hyperresponsiveness in Chinese schoolchildren.