The aim of this study was to compare a recent multiple allergosorbent chemiluminescent assay (MAST-CLA) with the RAST for the diagnosis of inhalant allergic disease in 232 patients with rhinitis and/or bronchial asthma. As judged by concordance of clinical history, skin prick tests to a range of six allergens common to our geographic area, and by nasal provocation tests, 70 patients were non-allergic and 162 allergic: 70 to grasses, 46 to mites, four to mugwort, eight to pellitory, and 34 were sensitive to several allergens. In our patient sample that, among other things, comprises subjects with fairly rare monoallergies, MAST-CLA testing gave results which closely corresponded to positive RAST for the allergens studied, and demonstrated a close correlation with the diagnosis of inhalant-specific allergy. Our results showed that, for overall allergens, MAST-CLA was lightly less sensitive and more specific than RAST (the two in vitro tests gave an identical overall efficiency).