SUMMARYWeighed amounts of lightly pulverized soil were drawn through a perforated aluminium plate and impacted on agar media in Petri dishes. This was done by placing the dishes in an Andersen air sampler, through which air was drawn at 14 l./min. The sampler was operated so that the soil was dispersed uniformly into 400 equally sized units/dish, each unit weighing 0·125 mg. These were transferred either to water‐agar medium to detect Pythium spp., or to Dox‐yeast‐agar medium for Fusarium oxysporum. The amount of each fungus in the soil was estimated from the frequency it was recovered from the transferred soil units. Results were more reproducible than by the usual soil‐dilution methods, and the method gave more uncontaminated cultures of Fusaria and Pythia.