An esterase from Lycoperdon pyriforme was characterized. The enzyme had a maximum activity at pH 8.0 and 40C with p-nitrophenyl acetate as a substrate. Km and Vmax values were calculated as 2.13 mM and 0.65 U/mg protein, respectively. The enzyme activity was conserved more than 90% over a broad range of pH (3.0–9.0) at 4C after 24 h of incubation. The activity increased 37 ± 3.6% after 120 min of incubation at 40C. Li+, Mg2+ and Ca2+ activated the enzyme 12 ± 1.8, 16 ± 2.5 and 15 ± 2.5%, respectively. The esterase was inhibited in different ratios by some detergents such as Triton X-114, Triton X-100, Tween 20 (Sigma Chemical Co., St. Louis, MO) and sodium dodecylsulfate. It retained most of its activity in the presence of methanol and dimethylsulphoxide at the final concentration of 10% (v/v). pH and moderate thermal stability of L. pyriforme esterase and its activity in some organic solvents could make it useful for some industrial purposes such as detergent and paper industry.