The reflection of green chemistry for the synthesis of a wide range of compounds via multi-component reaction systems is discussed in this paper. It also describes the most interesting, atom-economic Mannich and Mannich type reactions, their processes via green methods, solvents, green solvents, solvent effects, catalysts, catalyst effects, selectivity, kinetics, etc. They are indeed environmentally and ecologically benign. Keywords: Mannich reaction, Green Chemistry, Water.