An off-lattice simulation model for associative polymer gels as introduced recently (Groot, R. D.; Agterof, W. G. M. J. Chem. Phys. 1994, 100, 1649) has been applied to obtain the mechanical spectrum as a function of frequency and polymer concentration, using a Green-Kubo relation for the time-dependent modulus. Two stages of relaxation are observable in our simulations. The early-time decay is consistent with a -2/3 power law, whose form is insensitive to large variations in polymer concentration, association lifetime, and degree of association. The late stage, which relaxes like the end-to-end vector in the Rouse model, has a characteristic stress that scales as the cube of the concentration and a relaxation time that is proportional to the monomer-monomer dissociation rate. The simulation results have been compared with experiments found in the literature for several physical gels. The quantitative agreement calls into question other postulated mechanisms involving hydrodynamic interaction or reptation, since the simulation contains neither of these features. As an alternative explanation for the observed early-time decay, an explicit relation between the power law exponent and the polymer fractal dimension is given.