Competition and replacement interactions between species of wood-decomposing basidiomycetes were studied with a culture technique using various sized pieces taken from 6 cm diam. wood discs as a substrate. Based on field studies, 17 species of basidiomycetes, either primary decayers or late successional saprotrophs which show strict dependencies on certain preceding pioneer decayers in the field, were isolated and inoculated on the wood sectors. After precolonization, the sectors were attached to each other pairwise in various species combinations and incubated on water agar. The discs were regularly inspected and photographed for detection of mycelial overgrowth. After 6 months, samples were taken from the wood of the sectors and cultured for identification of prevailing mycelia. Measured by the replacement of opposing fungi, the selective late successional species are more combative than the primary decayers. Species of Antrodiella had the greatest competitive success. The results of our experiment corresponds well with field observations and explain, at least partly, the physiological background of the interactions.