The intertidal crustaceans on the Chilean coast are characterized by high diversity and niche specialization. The present study applied a size-overlap null model analysis for intertidal decapod communities in a central Chilean rocky beach (El Quisco, 32 degrees 24'S). The application of six models simulations revealed that there is a size overlap, confirmed by the results of all those six simulations. This means that the reported species would share their ecological niches. The results agree with the first classical ecological descriptions for Chilean intertidal decapods at a local scale and support the observations for similar species on the southern Pacific and southern Atlantic coasts, and the results of the null model agree with a first comparative study of decapods in the north and on the central Chilean rocky coast.