The kinetics of cyclopolymerization of N,N' -methylenebisacrylamide (MBA) was carried out using peroxydisulfate ion as initiator. The rate of polymerization, Rp, was found to be proportional to [M] and [S2O82-]1/2for the uncatalyzed system. A cyclopolymerization mechanism was found to fit the experimental results. The k21/kt1/2value for MBA polymerization was evaluated. Evidence in favor of the cyclopolymerization mechanism is provided. The addition of Ag ion enhances Rp.