Cancer is a deadly disease with complex pathophysiological nature and is the leading cause of death worldwide. Traditional diagnosis methods often detect cancer at a considerably critical stage and the conventional methods of treatment like chemotherapy, radiation therapy, targeted therapy, and immunotherapy have several limitations, multidrug resistance, cytotoxicity, and lack of specificity are a few examples. These pose substantial challenge for effective and favourable cancer treatment. The advent of nanotechnology has revolutionized the face of cancer diagnosis and treatment. Nanoparticles, which have a size range of 1-100 nm, are biocompatible and have special optical, magnetic, and electrical capabilities, less toxic, more stable, exhibit permeability and retention effect, and are used for precise targeting. There are several classes of nanoparticles each having their own sets of unique properties. NPs have played an important role in the drug delivery system, overcoming the multi-drug resistance, reducing the side-effects as seen in conventional therapeutic methods and hence able to solve the limitations of conventional methods of diagnosis and treatment. This review discusses the four major classes of nanoparticles (Lipid based NPs, Carbon NPs and Metallic NPs and Polymeric NPs): their discovery and introduction in medical field, unique properties and characteristics, advantages and disadvantages, sub-categories and characteristics of these categories, major area of application in Cancer diagnosis and treatment, and latest methodologies where these are used in cancer treatment.