In the recent years, there has been a growing interest in the development of nanoparticles based targeting agents for the tumor diagnostics and therapeutics. This is because of their potential to detect the tumor and treat the diseased tissue at the cellular and molecular level. In this respect nanoscale magnetic materials have shown a very promising therapeutic concept and offer a new perspective for the diagnostic and target drug delivery approach. The magnetic nanocarriers have the ability to accumulate at any desired pharmacological site just by the guidance of external magnetic field. But, the interactions of these magnetic nanocarriers with the biological environment are rare and depend largely upon their surface chemistry and size. To increase the interactions and achieve the desired pharmaceutically acceptable delivery system, the surface of magnetic nanocarriers is modified in various ways by coating with organic polymers and inorganic metals or oxides. On the basis of surface characteristics, a number of effective magnetically driven therapies have been proposed by many researchers and protected through patents time to time.