Hydrogel are three-dimensional, cross-linked networks of water-soluble polymers. Hydrogels can be made from virtually any water-soluble polymer. Injectable hydrogels are hydrogels which can given by parenteral route by use of injection and syringe. Such hydrogels are of particular interest because drugs, proteins, and cells can be easily incorporated into polymer solutions prior to administration.  Injectable hydrogel administrated in solution form by use of standard needles and syringes, it solidifies upon contact with aqueous body fluids to form gel. Drug release occurs over time as polymer biodegrades. This review will provide summary of recent progress in Injectable hydrogel, polymer used and method of preparation of Injectable hydrogel, evaluation of hydrogel and recent application of Injectable hydrogel. Key words: Hydrogel, Injectable hydrogel, Thermal and pH sensitive Injectable hydrogel, novel drug delivery system of Injectable hydrogel.