The resistance (R-x) and capacitance (C-x) in aqueous NaCl solutions across peritoneal membrane of young buffalo were recorded as functions of concentration, temperature, and frequency. The values of membrane resistance (R-m), capacitance (C-m), reactance (X-x), and impedance (Z) were computed. The pattern of R-x, R-m, X-x, and Z, with electrolyte concentration is similar to each other irrespective of their variations with temperature or applied frequency. The values of electrical double layer capacitance (C-d) were calculated. Plots of C-d versus square root of NaCl concentration gave straight line. The increase in capacitance with increases in concentration and temperature is rapid in the low concentration range and slows down with successive increases in concentration. These values, however, decrease with increase in applied frequency. Z-values record decrease with increases in electrolyte concentration and applied frequency. Increase in electrolytic concentration facilitates the permeation of ions across peritoneal membrane. This may be ascribed to the accumulation of ions within the membrane as well as to the electrical double layer formed by the counter ions at the membrane/electrolyte interface. (c) 2006 Elsevier B.V. All rights reserved.