A new precursor of halamine compounds, 3-methylol-2,2,5,5-tetramethylimidazolidin-4-one (MTMIO), was synthesized by methylolation of 2,2,5,5-tetramethylimidazolidin-4-one (TMIO) and characterized by H-1-NMR and FTIR. By chemically reacting MTMIO with cellulose, TMIO rings were successfully grafted onto cellulose-containing fabrics. After a subsequent chlorination, the treated fabrics were converted to halamine structures, which then demonstrated effective antibacterial efficacy. As expected, the halamine structure generated from TMIO is much more stable, and therefore, the biocidal functions of the finished materials are more durable. The results indicated that this halamine structure could survive repeated home laundering and would require less frequent chlorine recharging to maintain the biocidal properties. (C) 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2418-2425, 2003.