Considerably stable enzymatic fuel-cells (single cell and 5-cells stack) were prepared by using chitosan based membranes along with glucose oxidase attached bioanode. Continuous operation of fuel-cells were monitored under short circuit conditions reaching half-life over a week. Detailed analysis for the effects of pH, temperature, buffer types and concentration on different type of in-house produced chitosan membranes were performed by electrochemical impedance spectroscopy (EIS). EIS was utilized to observe, total electrolyte resistance, charge transfer properties, mass transfer and double layer effects on integrated fuel cells (single cell and 5-cells stack). Performance of the fuel cells was also analyzed by the polarization experiments. Current density of the fuel cell increased at higher operation temperatures not only due to better enzyme kinetics, but also due to increase in electrolyte (membrane+buffer solution) conductivity. Buffer concentration in the fuel (glucose) solution was found as an important parameter. Under optimum fuel cell operation conditions (i. e. 30-40 degrees C, pH 5 0.3 M buffer solution), maximum current densities of 3.0-3.2 mA cm(-2) were reached. Low-power devices (i. e. a calculator, step motor) were powered with 5-cell stack producing 3 mW at 1.3 V.