[en] The aim of our work was comparative study of such responses of microscopic fungi as positive radiotropism reaction and photostimulation. Positive radiotropism reaction was observed just among fungi isolated from accident zone of ChNPP. It was chose 10 strains with clear radiotropic reactions. All of them were stimulated by white light of low intensity. Most noticeable parameter was primary mycelium length (its stimulation was 35 - 167% comparing to control samples). The coincidence of radiotropism and photostimulation reactions of micromycetes, which had clear radiotropic reactions on the level of primary mycelia, was absolute. Obtained differences were only quantitative