In this study we have investigated the frequency dependence of bilayer lipid membranes for a series of glycerylmonoolein/ n-decane bilayers in various aqueous ionic solutions containing the ionophore valinomycin. Reliable values of membrane capacitance and conductance were obtained over the frequency range 0.2 - 200 KHz using an automatic balancing bridge under the control of a microprocessor unit. The admittance data was then normalized and curve-fitted to produce relaxation times and amplitudes from which the kinetic rate parameters, as deduced from a single slab dielectric membrane model, were calculated. These ac experimental rate constants were then compared with those obtained from charge-pulse relaxation methods.