The conditions for the synthesis of colloidal solutions of silver nanoparticles by galvanic replacement in an ultrasonic field and the AgAuNP binary system by galvanic replacement have been studied. It has been shown that colloidal solutions of stabilized nanoparticles with absorption maxima at 410 nm (AgNPs) and 540...560 nm (AgAuNPs) are formed in solutions of sodium polyacrylate and metal precursors of AgNO3 and H[AuCl4]. The synthesized AgAuNPs are spherical in shape and their size does not exceed 20 nm.