This chapter summarizes recent developments in magnetic materials, including magnetic nanoparticles and magnetic nanocomposites, synthesized using polyacrylamide gel technology, for application purposes including photocatalysts, multiferroic materials, magnetocaloric materials, and solid oxide fuel cells. The polyacrylamide gel route is a fast, reproducible, cheap, and easy to scale-up method for obtaining highly dispersed nanopowders and nanocomposites. The reaction mechanisms and key influencing factors for the preparation of highly dispersed magnetic nanopowders and nanocomposites have been discussed based on experimental results. By appropriately selecting chelating agents/initiators and controlling the unique physicochemical processes, magnetic nanopowders or nanocomposites fabricated using polyacrylamide gel technology are promising for wide applications in catalysis, pigments, magnetocaloric materials, magneto-optical devices, and magneto-electronics.