The effect of current density on the cell performance was investigated in a coin type molten carbonate fuel cell. The cell temperature was 700^oC under atmospheric condition. The three different of current densities, 150, 300, and 450 mA/cm² were used. The cell performance with respect to the current density was analysed via steady-state polarization, step-chronopotentiometry, and impedance methods. The electrochemical analyses revealed that cell performance rapidly degraded by increasing current density. This may result from decrease of active surface area caused by electrolyte loss. This work reports that life of MCFC strongly depends on current density.