The feeding ecology of most Oecobius species is poorly understood; nevertheless, the limited literature available suggests that obligate myrmecophagy is common in this genus. Recent evidence suggests that some species might do not share this trait, but could be locally specialized predators. We describe the diet and prey selectivity of the spider Oecobius concinnus (Simon 1893), a common pantropical species. Samplings of actual and potential prey for this species were made in the city of Ibagué, Colombia. Ants were the dominant prey. Other prey included in its diet were dipterans. These results suggest that O. concinnus is not an obligate myrmecophagous spider. Nevertheless, further studies will evaluate other aspects of the biology of this species to reveal its trophic strategy.