This invention relates to a chemically modified hyaluronic acid and salts thereof, which are obtained by O-acylating, alkoxylating or crosslinking a complex consisting of hyaluronic acid or a salt thereof and a cationic compound in a nonaqueous solvent, and a process for the production thereof. The nonaqueous solvent used in the invention is preferably one or more solvents selected from the group consisting of chloroform, toluene, methylene chloride and heptane.