Copolymerization of diallyldimethylammonium chloride (DADMAC) with 2-(diallyl(methyl) ammonio) acetate (DAMA) was studied. A homologous series of random copolymers (poly(DADMAC-co-DAMA)) with the DADMAC:DAMA ratio equal to 3:7 was investigated by dynamic and static light scattering, viscometry, and flow birefringence in 0.1 M NaOH solutions with the addition of NaCl (up to 1 M). The Mark-Kuhn-Houwink equations were obtained. It was established that decrease in the concentration of low molecular weight salt leads to sharp increase in thermodynamic quality of solvents, and, therefore, in swelling of the macromolecules. Equilibrium rigidity of the studied copolymer was determined as 5 nm. Conformational behavior of poly(DADMAC) (polyelectrolyte), poly(DAMA) (polyzwitterion) and poly(DADMAC-co-DAMA) with the DADMAC:DAMA ratio equal to 3:7 was investigated in solutions at different ionic strength values. It was established that at NaCl concentrations below 0.1 M, copolymer exhibits properties typical of polyelectr