Currently, there is a growing interest in obtaining and studying the biologically active compounds from higher basidiomycetes, such as Ganoderma lucidum, Lentinus edodes and Inonotus obliquus[1], but the techniques for safe long-term storage are time-consuming, susceptible to contamination, and do not prevent genetic and physiological changes during long-term maintenance [2]. A recent strategy for obtaining biologically active compounds is using mycelia submerged cultures of these mushrooms, cultured under controlled laboratory conditions [1]. However, obtaining spores of these fungi under these conditions is difficult, and in most cases the way to obtain the spores is unknown [1]. Therefore, the strategy for mycelium storage seems to be more appropriated and simple.•A modification of Castellani's method [3–7] is proposed for higher basidiomycetes, by using the mycelium of Humphreya coffeata (Berk.) Stey., whose culture filtrates demonstrated bioactivity against lymphoma cells [8].•H. coffeata (Berk.) Stey. was grown on malt extract agar with filter paper disks that were removed after 4 days, placed in tubes with sterile distilled water, and stored at 4 °C.•Filter paper disks with H. coffeata (Berk.) Stey. stored at 4 °C were confirmed to be viable for up to 18 months, with no visible morphological alterations.