The huge diversity and applications of various forms of hydrogels in medicine in last few decades have come up with one of the innovating forms of hydrogels i.e., “Nanogels” (NGs). NGs are the three-dimensional hydrogel materials, with sizes in the nanoscale range. They are composed of synthetic or natural polymers or a combination of both. By varying their chemical composition, their characteristic properties such as their size, charge, porosity, and others, they can be tuned or tailor-made. Along with their unique physical properties, they exhibit good swelling behaviour, stimuli-responsiveness, and biocompatibility, and encapsulation of guest molecules, protecting their cargo from degradation and delivering it at targeted sites. These nanoforms of hydrogels are being extensively explored by researchers for various medical applications today, some of which are discussed in the present chapter.