Neosartorya (N.) fischeri (Wehmer) Malloch and Cain is a significant agent causing molding of canned fruits. This genus made up 49.2% of all strains identified in 1989 from samples of molded canned fruit applied to the authors' laboratory by a canning plant. Ecology of this significant genus has been little studied. In the present work, 31 soil samples and 34 samples of cereal substrates from various localities were examined. Samples (10 g each) were placed into Sabouraud agar with 150 mg Rose Bengal/L and exposed to 70°C for 60 min. No colonies of N. fischeri could be isolated from one soil sample; in 30 samples the numbers of colonies ranged between 1 and 149 per sample, with an average of 27.6 colony forming units of N. fischeri per 10-g soil sample. N. fischeri as isolated from only three samples of cereal subtrates, at 1,6, and 7 colony forming units/10 g. Further studies are needed to elucidate factors determining the occurrence of thermoresistant propagule of N. fischeri in soil.