An extracellular ${eta}$-glucosidase was purified 154-fold to electrophoretic homogeneity from the brown-rot basidiomycete Fomitopsis palustris grown on 2.0% microcrystalline cellulose. SDS-polyacrylamide gel electrophoresis gel gave a single protein band and the molecular mass of purified enzyme was estimated to be approximately 138 kDa. The amino acid sequences of the proteolytic fragments determined by nano-LCMS/MS suggested that the protein has high homology with fungal ${eta}$-glucosidase that belong to glycosyl hydrolase family 3. The $K_ms$ for p-nitorophenyl-${eta}$-D-glucoside (p-NPG) and cellobiose hydrolyses were 0.117 and 4.81 mM, and the $K_{cat}$ values were 721 and 101.8 per sec, respectively. The enzyme was competitively inhibited by both glucose ($K_i$= 0.35 mM) and gluconolactone ($K_i$= 0.008 mM), when p-NPG was used as substrate. The optimal activity of the purified ${eta}$-glucosidase was observed at pH 4.5 and $70^{circ}C$. The F. palustris protein exhibited half-lives of 97h at $55^{circ}C$ and 15 h at $65^{circ}C$, indicating some degree of thermostability. The enzyme has high activity against p-NPG and cellobiose but has very little or no activity against p-nitrophenyl-${eta}$-lactoside, p-nitrophenyl-${eta}$-xyloside, p-nitrophenyl-${alpha}$-arabinofuranoside, xylan, and carboxymethyl cellulose. Thus, our results revealed that the ${eta}$-glucosidase from F. palustris can be classified as an aryl-${eta}$-glucosidase with cellobiase activity.