An aerobiological study of three different localities of the Auckland region using Burkard volumetric spore traps was conducted for a 12 month period from September 1979 to August 1980. High counts were recorded of various types of fungal spores of both unknown and recognised potential allergens but the basidiospore group was dominant at all sites forming greater than 50% of the total air spora. Seasonal periodicities as well as regional variations in spore concentrations of five generic group viz Ganoderma, Leptosphaeria, Cladosporium, Alternaria and Aspergillus-Penicilium were recorded. These exhibited summer and/or autumn peaks. The diel periodicities recorded for Ganoderma and Leptosphaeria were of nocturnal type. Cladosporium was diurnal and Aspergillus-Penicillium did not display any clear periodicity. The hospital admissions of acute asthma sufferers were recorded for the period January 1979 to December 1980. The seasonal pattern of airborne basidiospores of the region and the pattern of acute asthma admissions indicate a close relationship between the two.