We assessed prevalences of symptoms of asthma, allergic rhinitis, and atopic eczema and their associations with environmental exposures among school children living in high altitude and rural Tibet. After watching an asthma symptom video, 2.8% of the children reported ever wheezing at rest and 1.4% ever severe wheezing. Residential dampness problems were the only environmental exposure that was clearly associated with children's symptoms (odds ratios 1.3 to 2.5), even if several other exposures were common. The low symptom prevalences are in accordance with the hypothesis that the western lifestyle in some way increases the risk of asthma.