Nanotechnology explores a variety of promising results in the different area at molecular level. Nanoparticles (NPs) are tiny materials with size ranges from 1-100 nm and classified on the basis of their size, shape, dimensions nature, composition and other properties. Nanoparticles are synthesized by using top-down and bottom-up approach. Out of that the green synthesis method under the principle of bottom-up approach is widely exploited as it is a most economic and ecofriendly method for NPs synthesis. A nanoparticle possesses unique physical, chemical and magnetic properties because of that they have many applications in various fields like agriculture, food, cosmetics, energy generation, environmental bioremediation, and especially in pharmaceutical and medical field. In medical field there is tremendous use of NPs for imaging, detection, and therapeutic purposes. This review gives the brief information about types, synthesis characterization and applications of nanoparticles.