This study was performed with the aim of determining the "natural" wood preferences of subterranean termites (Isoptera) in a field feeding experiment, giving a choice between a control (Pinus sp.) and test woods: three species of Eucalyptus. Feeding preference order of subterranean termites was Pinus sp. > Eucalyptus robusta ≅ Eucalyptus urophylla > Eucalyptus pellita by the percentage of subterranean termite-damaged wooden stakes at 30-, 45-, and 60-day exposure periods in the field. Three species of subterranean termites were identified: Heterotermes longiceps (Snyder) (Rhinotermitidae), Coptotermes gestroi (Wasman) (Rhinotermitidae), and Nasutitermes jaraguae (Holmgren) (Termitidae). This is the first record of occurrence of H. longiceps in the state of Rio de Janeiro. Unidentified fungi species of Basidiomycetes infected the wood stakes of all forest species tested; although none of them were attacked by subterranean termites.