The present invention relates to a biodegradable hydrogel comprising bonds which are hydrolyzable under physiological conditions. More particularly, the hydrogel consists of two interpenetrating polymer networks interconnected to one another through hydrolyzable spacers. In addition, the invention relates to a method for the preparation of a hydrogel, wherein macromolecules, e.g., polymers which contain bonds which are hydrolyzable under physiological conditions, are cross-linked in an aqueous solution.