The goal of this study was to identify the demography of the weed Echinochloa crus-galli and the effect of post-dispersal seed predation in maize fields. In the presence of seed predators, the number of seedlings was reduced, but density-dependent processes during seedling emergence, seedling survival, and fecundity per capita compensated the losses. In summary, to control weeds, seed predation needs to be combined with other control measures that target the seedling survival and fecundity.