In-situ Ni and ex-situ NiO(Li) cathodes were fabricated by cold pressing using Ni powder and Li₂CO₃(in case of ex-situ cathode) with paraffin wax as a binder. The characteristics of in-situ and ex-situ cathodes according to the sintering temperature were examined. Also the behavior of the in-situ and ex-situ cathodes under the MCFC operation condition were investigated in this study. The optimum sintering temperature was 800℃ of neck growth step leading to the porosity of about 70% and strength of about 350MPa. To obtain reasonably high electric conductivity in ex-situ cathode, the sintering temperature was chosen to be below 950℃ to maintain the cation fraction of L^+ in the range of 0.02∼0.06. In terms of the Ni-dissolution rate, ex-situ cathode was more efficient than in-situ cathode in the long-term operation except the initial 24hr. Corrosion product was Li₂NiO_(10) at the in-situ and ex-situ cathodes.