Novel linear and crosslinked polyelectrolytes based on acetoacetic ester and acrylic acid were synthesized for the first time via Michael addition reaction followed by radical polymerization. The structure and properties of polyelectrolytes were characterized by FTIR, Raman and NMR spectroscopy, TGA, DSC, GPC, viscometry and potentiometric titration. Considerable influence of water content on the swelling rate of hydrogels was established. The swelling-deswelling properties of hydrogels were studied in dependence of pH, ionic strength and in water-organic solvent mixtures.