Hyaluronic acid (HA) is a glycosaminoglycan composed of alternating N-acetyl-D-glucosamine and D-glucuronic acid moieties. HA is an ubiquitous component of connective tissue where it forms matrix and plays an important role in the maintenance of matrix structure and water balance. The viscoelastic properties of HA derivatives and nonimmunogenicity has provided its use in a number of pharmaceutical applications. Ability of HA to create and fill space by organizing and modifying the extracellular matrix is widely used for soft tissue augmentation to limit age-related and photoinduced skin aging, but also may be used for correction of facial lipodystrophy and to prevent reccurence of hypertrophic scars or keloids. Furthermore HA may be employed as a surgical aid in ophthalmology or to reduce knee pain and joint motion in patients with osteoarthritis. In children HA may become an alternative to the open surgery for the management of vesicoureteral reflux.