Using a mixed within-between design, this study was designed to evaluate the sensorial and cognitive/evaluative aspects of bronchoconstriction induced by progressive methacholine inhalation. 25 asthmatic patients and 15 normal controls were given two consecutive bronchoconstriction tests, inducing a fall of > 30% of the forced expiratory volume in 1 sec (FEV1), which was measured after each inhalation of methacholine. Immediately before each FEV1 measurement, Ss rated perceived bronchial closing, discomfort of breathing and anxiety, as well as the need to use a bronchodilator. In addition to state-anxiety, after each bronchoconstriction test asthma symptoms were evaluated by means of a Free Symptom Report and the Asthma Symptom Checklist. The results show that during the first test, asthmatic patients perceived their symptoms more accurately than non-asthmatic controls. However, during the second test, asthmatic patients became less accurate, while normal controls increased their accuracy of symptom report. These changes were not parallelled for the Free Symptom Report or the Asthma Symptom Checklist. These results suggest that, depending on situational circumstances, patients rely on their cognitive schemata to report asthma symptoms. Need for bronchodilator use was related to perceived discomfort but not to actual or perceived bronchial closing. Clinical implications of this study are discussed.