Disclosed is a process for the preparation of hydrogels consisting of crosslinked glycosaminoglycans, which comprises: a) reacting at least one hybrid cooperative complex obtained by heating aqueous solutions of low- and high-molecular- weight glycosaminoglycans at 80-160°C with a diepoxide as crosslinker in a ratio with the complex ranging between 0.1 and 1 equivalents, preferably between 0.2 and 0.4 equivalents, the concentration by weight of the complex in the solution ranging between 1% and 15%, preferably between 2% and 10%; b) purifying by dialysis, ultrafiltration and diafiltration.