THE PRESENT INVENTION IS RELATED TO HYALURONIC ACID COMPOSITIONS CONSISTING IN A BINARY MIXTURES OF HYALURONIC ACID SAMPLES HAVING MAINLY DIFFERENT WEIGHT-AVERAGE MOLECULAR WEIGHT AND THEN DIFFERENT RHEOLOGICAL PROPERTIES IN AQUEOUS SOLUTION. THE RESULTING COMPOSITIONS HAVE DEMONSTRATED PECULIAR RHEOLOGICAL BEHAVIOUR WITH A BALANCE BETWEEN VISCOSITY AND VISCOELASTICITY. ACCORDINGLY, THESE COMPOSITIONS OF HYALURONIC ACID ARE USEFUL FOR TREATMENT OF JOINT DISEASES BY INTRA-ARTICULAR ADMINISTRATION OR EXTRA-ARTICULAR APPLICATION IN SOFT TISSUE DISORDERS.