A novelnucleoside, 9-β-d-ribopyranosylpurine (2), along with three known nucleosides, adenosine (1), uridine (3) and nebularine (4), were isolated from the edible mushroom, Tricholoma japonicum. The structure of 2 was determined as 9-β-d-ribopyranosylpurine by comparing the reported spectral data of 2 with that of a synthetic compound. Isolation of the glycoside, which contains the sugar ribopyranose