The aim of the study was the comparison of quantitative-qualitative structures of the fungi communities micromycetes in the chosen organic-muck soils. Sample points were located from desiccated but floodedpeatlands in Biebrza Valley. The analyzed soils belonged to the weakly mucked and was medium mucked. Qualitative structure of communities of soil fungi were different. The largest number of isolates and species was characterized by medium mucked soil. This means that increasing intensity of soil transformation favours greater diversity of fungi species in the communities growing in dehydrated peatland. The fungi are sensitive indicator of changes in the soil and the structure of these communities change with the changes in habitat conditions. The muck layers were occupited by fungi communities of much stronger diversifiedqualitative and quantitative structures than those found in deeper layers of peat. The fungi species most frequently met in the soil analyses included Penicillium simplicissimum, P. janczewskii and P. waksmanii along with Helicosporium vegetum.