In this study, a new cationic monomer 2-(3-indol-yl)ethylmethacrylamide (IEMA) derived from tryptamine was synthesized in a single step and characterized by Fourier transform infrared (FTIR), H-1-NMR, and C-13-NMR. Then, one-step preparation of novel poly[2-hydroxyethylmethacrylate-c-2-(3-indol-yl)ethylmethacrylamide], or p(HEMA-c-IEMA), copolymeric hydrogels has been performed successfully with IEMA and 2-hydroxyethylmethacrylate (HEMA) as monomers using free radical aqueous polymerization. The hydrogels were characterized with scanning electron microscopy, FTIR, elemental analysis, thermogravimetric analysis, and texture profile analysis instruments. p(HEMA-c-IEMA) hydrogels were used for swelling, diffusion, drug release, and antibacterial activity studies. The drug-release behavior of the hydrogels was determined as a function of time at 37 degrees C in pH1.2 and 7.2. The swelling and drug-release studies showed that an increased IEMA amount caused a higher increase in swelling and drug-release values. Additionally, zero-order, first-order, and Higuchi equation kinetic models were applied to the drug-release data, and the data fit well in the Higuchi model, and the Peppas power-law model was applied to the release mechanism. Finally, the antibacterial activities of the hydrogels were screened against Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Salmonella typhimurium). (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45550.