Uracil adsorption at Bi(h k l) has been studied using impedance spectroscopy method. The limiting adsorption potential shift, Gibbs energy of adsorption -&UDelta; G&DEG;(A) and interaction constant values α in the Frumkin isotherm have been calculated and compared with the corresponding data for Hg [V. Brabec, S.D. Christian, G. Dryhust, J. Electroanal. Chem. 85 (1977) 389; V. Brabec, S.D. Christian, G. Dryhust, Biophys. Chem. 7 (1978) 253]. It was found that the values of |-&UDelta; G&DEG;(A)| increase in the order Hg < Bi(111) < Bi(011(1 overbar)), but the values of α are higher for Bi(h k l) compared with Hg [V. Brabec, S.D. Christian, G. Dryhust, J. Electroanal. Chem. 85 (1977) 389; V. Brabec, S.D. Christian, G. Dryhust, Biophys. Chem. 7 (1978) 253]. The values of the limiting adsorption potential shift are comparable for the Hg and Bi(h k l) electrodes. © 2005 Elsevier B.V. All rights reserved.