This study investigated two schools, one of which had previous mold problems. Pupils aged 6 to 13 yr were investigated using a questionnaire on symptoms and a skin prick test. The amount of airborne (1 → 3)-β -d-glucan was measured in the classrooms. The levels were significantly higher in the problem school than in the control school (15.3 versus 2.9 ng/m3). The extent of respiratory as well as general symptoms was higher among the pupils in the problem school. Among the atopics, the extent of symptoms of dry cough, cough with phlegm, and hoarseness was similar to the nonatopics in the control school, but significantly higher in the problem school. The results suggest that (1 → 3)-β -d-glucan, either by itself or as an indicator of molds, is a risk indicator of airways inflammation.