Nanohybrid gels based on polyacrylamide (PAAm) and colloidal silica nanoparticles were synthesized by free radical polymerization. The influence of chemical cross-links and radical initiators on the dynamics of the network and the nanoparticles were studied by dynamic light scattering (DLS). In ensemble averaged autocorrelation functions we observed two decay modes in the hybrid gels, a gel mode and a Brownian diffusion mode of the silica nanoparticles particles at a concentration higher than 0.03%. An increase in the chemical cross-linking ratio did not influence the gel mode while the silica nanoparticles diffusion mode was slowed down. At lower silica concentrations, we observed (1) a higher scattered light intensity than for a silica suspension and for a gel without silica, (2) an increased plateau value, and (3) no silica diffusion mode in the autocorrelation function. These results indicate that the hybrid gels were more heterogeneous. The gelation time decreased in the presence of silica at low concentration compared with the corresponding gel without silica, suggesting that the transfer of radicals from persulfate to silica surface occurs and that PAAm chains grow from the surface creating increased heterogeneity in the gels.