Hyaluronic acid or Sodium hyaluronate (HA) is a naturally occurring, biodegradable biopolymer of interest; which is found to be present in synovial fluid and connective tissues. It also found in the vitreous fluid of the eye; mostly of bacteria and higher animals. Hyaluronan synthases; a membrane protein takes part in HA synthesis. The formed HA gets degraded by enzyme hyaluronidases. HA plays an important role in fields of biomedical and tissue engineering. Moreover, biologically; it plays principal role in maintaining elastoviscosities of connective tissues and eye vitreous fluid, which controls tissue hydration, lubrication of movable body parts, water transport and moisturizer. This review undertakes consideration of HA in many aspects such as, its chemistry, biological importance, physiological and pathological functions, current and future trends and applications. © 2020, Advanced Scientific Research. All rights reserved.