An extracellular lipase produced by Pseudomonas aeruginosa KF 853103 was purified to 15-fold with a specific activity of 1671.9 pkat mg^-1 protein after ammonium sulphate precipitation and DEAE-cellulose column chromatography. The purified enzyme showed pH optima of 8.0 and temperature 40°C and was relatively stable within the temperature range of 30-40°C. The enzyme retained 96.5, 80.3 and 93.4 of its maximum activity in the presence of methanol, ethanol and acetone, respectively. However, the relative activity of enzyme was comparatively less in the presence of hexane and propanol (64.8 and 52.8%). The K_m and V_max values for lipase were found to be 0.136mM and 71.4 pkat ml^-1, respectively. From the study of effect of temperature on K_m and V_max, free energy change (ΔG), enthalpy change (ΔH), entropy change (ΔS) and energy of activation (E_a) were reported to be -23.2 kJ mol^-1, 15.9 kJ mol^-1, 124.7 J K^-1 mol^-1 and 19.1 kJ mol^-1, respectively.