Nanogels are the advanced technology in pharmaceutical sciences which has been most popular in effective drug delivery inside the body as well as topical treatment. Nanogels are promising and innovative formulation to deliver the drug at target site, hence it becomes a part of “Target Drug Delivery System”. Nanogels are composed of nanoparticles having physically or chemically crossed linked hydrogel porous structure that can be used as highly efficient and biodegradable carriers for the transport of drugs in controlled drug delivery. Nanogels have great potential in the Chemotherapy, Gene silencing therapy, Organ targeting and Delivery of bioactive substances. The main areas of the target for the nanogels have been tumors of brain, liver, skin etc. The formulations improve the effectiveness and safety of certain composition, which have been confirmed from in vivo study in animal models. In this article, we have discussed the basic mechanism of action of nanogels in vivo. And the possibility of using the nanosystems in improving the current therapies, diagnosis as well as clinical trial progress. Keywords: Nanogel, Nanoparticle, Nanocarrier, Drug Release, Stimuli responsive, Degradation, In vivo mechanism, Evaluation parameters.