Novel aromatic azo-containing pH-sensitive hydrogels were synthesized by a "one-step" polymer-polymer reaction of two precursors. Precursor A was synthesized by copolymerization of a new aromatic azo-containing monomer, N-(1-aminohexyl)-4-[[4-(methacryloylamino)phenyl]azo]benzamide (MA-AZO-NH2), with N,N-dimethylacrylamide, N-tert-butylacrylamide, and acrylic acid. Precursor B is a copolymer similar to precursor A that contains N-methacryloylglycylglycine p-nitrophenyl ester (MA-GG-ONp) instead of MA-AZO-NH2. Aromatic azo bonds of MA-AZO-NH2 in the polymer and in hydrogels were degradable in the presence of fresh rat cecum contents. Control hydrogels were synthesized by cross-linking polymer precursor B with a low molecular weight aromatic azo-bond-containing diamine. Modeling of network structure for both novel and control hydrogels was accomplished using a statistical branching theory (theory of branching processes). The theoretical values and experimental data were compared.. Conclusions were made for the impact of synthetic mixture compositions and the methods of hydrogel synthesis on the structure of the resulting hydrogel networks.