Methacholine (MCH) is used to perform the bronchial challenge test for the diagnosis of asthma where it is necessary to determine if an individual has hyper-responsive airways. The aim of this work was to develop a new method for MCH challenge test using pre-metered respirable MCH powders at different doses for performing brochial challenge studies. The availability of a series of pre-metered doses gives greater control on aerosolized dose and fine particle dose (respirable dose), improving the accuracy and repeatability of the test. A dosimetric challenge test, comparing MCH dry powder and MCH solution for asthma detection, was performed in eighteen subjects.