The present invention relates to a method of producing methyl esters of a hyaluronic acid, said method comprising the steps of: (a) providing a suspension comprising the acid form of the hyaluronic acid in methanol; (b) adding an organic solution of trimethylsilyldiazomethane to the suspension and mixing, whereby methyl esters of hyaluronic acid are produced; and (c) recovering the hyaluronic acid methyl esters.