Traditionally, nearly 40% of the new chemical entities (NCEs) identified by pharmaceutical industry screening programs have failed to be developed because of poor water-solubility, which makes their formulation difficult or even impossible. The solubility issues complicating the delivery of these new drugs also affect the delivery of many existing drugs. The various traditional and novel techniques that that can be used for solubility enhancement of BCS Class II drugs are briefly discussed in this article. The Traditional techniques that has been discussed in this article includes use of co-solvents, Hydrotropy, Micronization, change in dielectric constant of solvent, amorphous forms, chemical modification of drug, use of surfactants, inclusion complex, alteration of pH of solvent, use of hydrates or solvates, use of soluble prodrugs, application of ultrasonic waves, functional polymer technology, controlled precipitation technology, evaporative precipitation in aqueous solution, use of precipitation inhibitors, solvent deposition, precipitation, selective adsorption on insoluble carriers. Novel drug delivery technologies developed in recent years for solubility enhancement of insoluble drugs are size reduction technologies, lipid based delivery system, micellar technologies, porous micro particle technology. Solid Dispersion Technique and various types of solid dispersion systems have also been explained briefly.