The growth of particles of lithium aluminate in the electrolyte matrix of molten carbonate fuel cells is problematic in that the particles agglomerate in the electrolyte with the passage of time, thereby decreasing retention of the alkali carbonate melt. To further elucidate the growth mechanism of lithium aluminate particles, the effects of temperature, Pco2, and Li/K ratio in the melt on particle growth were determined. Equilibrium solubility measurements of lithium aluminate in a molten carbonate were also performed under various conditions. The results indicated that particle growth depends on the basicity of the electrolyte.