Field experiments were carried out to assess the entomofauna, effect of predatory arthropods, intercropping with sorghum and insecticidal treatments on pest density and damage of soybean in a southern guinea savanna zone of Nigeria. The number of insects species (136), over threefold the number (40) reported in the zone a decade earlier, was associated with soybean. That was a fairly fast rate of colonization of the crop by insects. Predominant pest species included Halticus tibialis (Reut), Empoasca dolichi (Paoli) and Monolepta kraatzi (Jac). Predatory species were dominated by Pheidole sp and spiders. Defoliation was > 1%. Insects pest abundance did not significantly reduce crop yield. Intercropping with sorghum had no effect on soybean pest populations. Short intervals (5 years) of entomofauna surveys, regular studies of biology and spatial distributions of insects in soybean ecosystem, several sampling methods to take care of mobile and sedentary species and actual insect-damaged leaf portions (defoliation) rather than guesses would need to be carried out in order to provide information required to formulate an integrated pest management programme for this location.