In cultivation of the Basidiomycetes under aeration and agitation in an aqueous liquid medium containing saccharide as a carbon source and yeast extract, peptone, casamino acid and/or meat extract as nutrient, the initial charge of the medium is adjusted such that it is less than about 70% of the capacity of the fermentor used, and the medium or at least one component thereof is supplied additionally in portions as cultivation advances. Such control of the medium feed suppresses excessive foaming which occurs in the aqueous medium during cultivation, and allows smooth and efficient cultivation of the Basidiomycetes.