As compared  to emulsion, liposomes and polymeric microparticulate systems,  Nanostructured Lipid Carriers (NLC)  has  emerged as a  novel colloidal drug carrier system which has  gained a lot of popularity among researcher due to its applicability for various routes such as oral, topical and parenteral with embedded properties of site specific and controlled drug delivery with reduced side effects. Along with their advantages, some challenges such as low drug loading and drug expulsion from Solid Lipid Nanoparticles SLN during storage were needed to be addressed. These limitations were overcome in Nanostructured lipid carriers (NLC), which are second generation SLN. NLC accommodate the drug because of their highly unordered lipid structures. NLC can be administered via oral, ocular, pulmonary and intravenous routes. The present reviews correlate the types of NLC, preparation methods and characterisation of SLN and NLC. The review covers in brief the comparative study of SLN and NLC of some drugs by researchers.