This study investigated the lithiation of white Agaricus bisporus (common button) mushrooms using compost fortified with LiOH solutions at concentrations from 1 to 500 mg kg-1 compost dw. Apart from the highest level of fortification, the median Li concentrations in the cultivated mushrooms were elevated from 0.74 to 21 mg kg-1 dw (corresponding to compost fortification from 1.0 to 100 mg LiOH, kg-1 dw), relative to control mushrooms at 0.031 mg kg-1 dw. The bio-concentration potential for Li uptake in fruiting bodies was found to decrease at higher levels of fortification e.g. 50 - 100 mg kg-1 dw, and at the highest level - 500 mg kg-1, the mycelium failed to produce mushrooms. The fortification of the compost with LiOH appears to have had little, if any, effect on the co-accumulation of other elements such as Ag, Al, As, Ba, Cd, Co, Cr, Cs, Cu, Hg, Mn, Ni, Pb, Rb, Sr, Tl, U, V and Zn in the fruiting bodies, which generally occurred at the lower range of the results reported in the literature for cultivated A. bisporus. Thus compost fortification with LiOH provides an effective means of lithiating A. bisporus for potential pro-therapeutic use.