Bioavailability is a term used by several branches of scientific study to describe the way of chemicals absorbed by humans and other animals. But now Bioavailability has broad applications in environmental sciences as well as in pharmacology. At present about 10% of the drugs under investigation have bioavailability problems due to poor solubility. The poor solubility even makes it very difficult to performthe pharmacological screening of compounds for potential drug effects. Therefore there is a high need for intelligent drug formulations to achieve a sufficiently high bioavailability. Pharmacology also distinguishes between absolute bioavailability and relative bioavailability. Absolute bioavailability is the measurement of a medication once it passes through the gut and is released into the circulatory system. Relative bioavailability is a termused to compare different formulations of the samemedication, for example brand name versus generic. The important factor which affects the bioavailability of orally administered drugs is their poor solubility in biological fluids. Hence we have made an attempt to review the various approaches of enhancing the water solubility of the drug and their by enhancing the bioavailability.Afew approaches such as prodrug, solid dispersion , cosolvency, spherical agglomeration and inclusion compounds have been discussed which can be frequently employed in pharmaceutical industries with ease.