The thermodynamics of the low-level Ce dissolved in liquid Bi was determined by means of the electromotive force (EMF) measurement method using a cell consisting of molten chloride and liquid Bi at the temperature ranging from 735 to 937 K. The activity coefficients of Ce in Bi were deduced from the obtained EMF results. A considerable increase in the activity coefficient with temperature was observed in the Ce concentration range studied. The values of the molar excess formation free energy, the excess enthalpy change, and the excess entropy change of Ce dissolved in Bi were determined. The heat of formation of liquid Ce-Bi alloys (Delta H-Ce-Bi(M)) was deduced from the measured activity coefficient. There is a linear dependence of experimental (Delta H-Ce-Bi(M)) on the Ce concentration. The experimental results of (Delta H-Ce-Bi(M)) were compared with the values predicted by the Miedema's model.