Copolymerization of acrylic acid with new acrylamide biuret derivatives obtained was investigated. Reactivity ratios r 1 and r 2 of these monomers with acrylic acid were calculated. It was found that monomers of mono-and diacrylamide biuret derivatives are of cyclic structures and this fact specifi cally affects their activity in the copolymerization with acrylic acid.