A beta-glucosidase was purified from Periplaneta americana by chromatography on ion-exchanges, gel filtration and hydrophobic interaction columns. The preparation was shown to be homogeneous on polyacrylamide gel. The enzyme was purified 9.93-fold to a specific activity of 40.33 (U/mg of protein) and an overall yield of 1.54 %. SDS-PAGE revealed a single polypeptide of 43.8 kDa, thus indicating apparent homogeneity of the final enzyme preparation. Gel filtration chromatography showed that the enzyme was a 46.5 kDa monomeric protein. The purified enzyme exhibited pH and temperature optima at 3.6 and 55°C, respectively. The beta-glucosidase was stable at 37C and its pH stability was in the range of 3.0-4.0. The enzyme readily hydrolyzed p-nitrophenyl-beta-D-glucoside, cellobiose, cellodextrins, p-nitrophenyl-N-acetyl-beta-D-glucopyranoside, p-nitrophenyl-N-acetyl-beta-D-galactopyranoside and required strictly β-glyco configuration for activity. The specificity constants (Vmax/KM) values for N-acetyl-beta-D-Glucopyranoside, p-nitrophenyl-beta-D-glucoside and cellobiose were respectively 31.05 mM−1s−1, 12.47 mM−1s−1 and 4.59 mM−1s−1. It required no metal ion as a co-factor. Zn2+, Ba2+, pCMB inhibited the beta-glucosidase activity.