In this review article the analysis of the main problems related to the use of NiO as material for cathodes in Molten Carbonate Fuel Cells (MCFC) is reported. Thus, the most significant evidences of the mechanism of NiO dissolution have been reported as well as its correlation with the basicity of the carbonate melt, composition of the reactants gases and temperature. Some hypotheses described here have been also verified experimentally and the results of this validation are reported. In the final section, we have described the most promising alternative solutions to this problem and the advantages and shortcomings of these alternatives.