Nanofluid is a fluid containing nanometer sized (1-100mm) particles called nanoparticles. A nanofluid can be generated by suspending nanometer sized particles to the base fluids. Nanoparticles used in nanofluids are typically made of metals (Al, Cu), oxides (Al2O3, CuO, TiO2, SiO2), Carbides (SiC), nitrides (AlN, SiN) or non-metals (graphite, Carbon nanotubes).The materials which are in nanometer size possess unique physical and chemical properties. They can flow smoothly through micro-channels without clogging because they are sufficiently small to behave similar to liquid molecules. This fact has attracted much research into the investigation of the heat transfer characteristics of nanofluids.The nanofluids are useful in various industrial and nanotechnological processes such as cooling of electronic devices, vehicle cooling, nuclear reactor, heat exchanger, vehicle thermal management and many others. Magneto nanofluids have specific applications in biomedicine, optical modulators, magnetic cell separation, magneto-optical wavelength filters, silk float separation, nonlinear optical materials, hyperthermia, optical switches, drug delivery, optical gratings etc.