The Mild Combustion is a relatively novel combustion technique characterized by both an elevated temperature of reactants and an adiabatic flame temperature not higher than 1600K. These features are the results of several technological demands coming form different application fields. The main advantages derived by Mild Combustion concern both the combustion process itself and its applications. In the former case the pollution reduction, the increase of efficiency process and fuel flexibility has to be considered whereas the latter one is principally related to heat treatment process and wall confinement. In this paper, characteristics of Mild Combustion are discussed with particular regards towards the aspects of plant design. A general classification of the processes, where initial and adiabatic temperature values are different from characteristic ones of classical combustion system, is given. This classification leads to a definition of Mild Combustion process as a direct consequence of technological evolution and practical constrains, especially related to environmental problems. In this sense, the high temperature of reactants and the low adiabatic temperature, principally obtained using exhausts for both heat recovery and dilution, can not be considered independently. Application of Mild Combustion in practical systems infers the use of particular solutions because of high temperature of reactants involved. In the final part of the paper, specific solutions utilized in a laboratory mild combustor are presented.