To explore the use of oscillometry as a measure of airway responsiveness, 69 asthmatic children underwent histamine and methacholine bronchoprovocation using dosimeter-MedicAid (Jaeger Co.; Germany) and DeVilbiss nebulizers (DeVilbiss, Bornemouth; England). The mean increase in R5 resistance in challenge testing measured after methacholine with the dosimeter-MedicAid nebulizer was 77.14% compared with 65.05% using histamine. Using the dosimeter-DeVilbiss nebulizer, the mean increases in R5 resistance following methacholine and histamine testing were 57.50% and 59.36%, respectively. The resistance R5 over R20 significantly correlated with forced expiratory volume in 1 second (FEV1). The MedicAid produced a more aggressive challenge than the DeVilbliss nebulizer. Oscillometry can be used to monitor the level of airway hyperresponsiveness following bronchoprovocation tests.