Interactions between ants and plants and those involving homopterans were studied in 248 sampling points located within nine tropical decidous forest fragments in the Cauca river Valley, between january and june, 1997. A total of 352 interactions were recorded involving 91 plant species, 67 ant species and Homoptera belonging to nine families. 47% ofthe interactions involved ants using different plant structures (such as epiphyte roots, domacia, litter collected in branches and leaves, bracts and petioles of Heliconia spp.) as nesting sites or temporary refugia. The remaining 53% involved the collection of homopteran honeydew and sugary substances from extrafloral nectaries. Wasmannia auropunctata (17%), Dolichoderus bispinosus (11 %) and Brachymyrmex heeri (7%) were the most frequently recorded ant species. Heliconia stricta (8%), Philodendron sp. nov. (7%) and Passiflora coriacea (5%) were the most heavily used plant resources. Predominant relations could be described as generalist, in which ants exploited different plant resources opportunistically and plants appeared to be healthy even without their ant occupants.