In pharmaceutical observation, nanoemulsion is one of the chief dosage forms in delivering active ingredients to the objective area which has engrossed a great attention in recent years for its application in various fields. In the pharmaceutical field, nanoemulsions have been used as a drug delivery system through various systemic routes such as oral, topical and parenteral. Nanoemulsions are submicron sized emulsions which are used under high investigation as drug carriers for improving the delivery of therapeutic agents. The small droplets size 10-200 nm, high solubilization capacity, high interfacial area, low viscosity, transparent or translucent appearance, and high kinetic stability, make nanoemulsions used for various applications. These emulsions are easily produced in large quantities by mixing a water immiscible oil phase into an aqueous phase with high stress. These are prepared from surfactants, cosurfactants or cosolvents. In this review diverse aspects of nanoemulsion are highlighted i.e. method of preparation, characterization techniques like particle size, zeta potential, polydispersity, drug content advantages, disadvantages and particular importance on various application of nanoemulsion in different areas such as in cancer treatment, drug targeting, as a vehicle for transdermal drug delivery, selfnano emulsifying drug delivery system.