Aqueous solubility is one of the most influencing factors when it comes to bioavailability of the drugs. It is the main key for drug effectiveness and enhancing water solubility, which poses one of the greatest challenges in the pharmaceutical industry. Nearly half of newly developed drugs turn out to be insoluble or poorly soluble during initial screening process. Poor solubility limits drug delivery and formulation development. Various techniques have been developed to enhance solubility of poorly soluble drugs. Pharmaceuticals falling under the Biopharmaceutics Classification System (BCS) class II and IV are the main emphasis of this review as these drugs are of low solubility. The methods to improve drug solubility; solid dispersions, cyclodextrin complexation, dendrimers, nano-suspensions, co-solvency, pH adjustment, self-emulsifying drug delivery system, hydrotrophy, cocrystallization and ionic liquid formation are discussed.