Recent discoveries indicate that the materials are bought down in sizes in the range 1-100nm, these exhibits unique electrical, optical, chemical and pharmaceutical properties. Methods have now been established to obtain the monodispersed na nocrystals of various metallic and semi conducting materials, single walled and multiwalled nanotubes of carbon and other metallic and non metallic materials together with organic nanoma terials such as nanostructures composites with tailored functionalities. Carbon nanotubes (CN Ts) have great impact on the development of newer methodologies and devices useful for the anal ysis and the detection of various types of chemicals. The detection sensitivity can be increas ed many folds. The extraordinary properties of carbon nanotubes have led to demonstration of sever al applications of CNTs. But commercial realization of these CNTs and CNTs based devices re quire consistent quality of CNTs and these should be free of any impurity. Such demanding requ irements need development of elaborate purification and sorting of CNTs. In last few yea rs, Carbon Nanotubes (CNTs) have shown unexpected advantages in the field of cancer treatm ent and drug delivery systems. Present review article discuss in brief about the methods of synth esis, with purification as well as sorting techniques for giving different grades to different types of CNTs. These show very good adsorption properties which helps in the detection of various chemicals, toxic agents etc. Research done using CNTs for cancer treatment is al so discussed in brief.