This article outlines a comprehensive analysis of the microbial diversity of aerosols produced during screening in a green waste composting plant using both culture and molecular techniques. Bacteria, thermophilic actinomycetes and fungi were quantified in the aerosols. The structure of the microbial community was examined using a fingerprint technique and DNA libraries. The results show: (i) the very high diversity of bacteria and fungi in aerosols produced during the composting screening stage, (ii) the low percentage of cultivability for bacteria in aerosols, (iii) the abundance of Thermoactinomyces spp. and Aspergillus spp. in compost aerosols.