Lipid Nanoparticles have gained increased attention during the last few decades. These carrier systems offer many advantages over conventional drug delivery system, including protection of the entrapped active ingredient from environmental (pH) or physiological (immune system, enzymes) degradations, improved bioavailability, prolonged circulation time, sustained release of drug and site specific drug delivery, reduced dose and side effects. Solid Lipid Nanoparticles (SLN), has been reported as an alternative carrier system to liposomes. However, SLN show some disadvantages such as drug expulsion during storage, low drug loading and aggregation of the particles. Nanostructured lipid carriers are evolved as second generation lipid nanoparticles to overcome the limitations of SLN, by modifying SLN by incorporating liquid lipid to the solid matrix for better drug accommodation to increase drug loading and prevent drug leakage while preserving the physical stability of the formulation. This article describes the features, various preparation techniques, characterization techniques and the therapeutic applications of NLCs in topical drug delivery, brain, oral and pulmonary delivery.