This study aims to investigate the diversity of fouling and boring organisms damaging wood material at Turkish coasts. Trials were carried out at six harbour sites throughout the seas surrounding Turkey. Various Euopean and tropical wood samples were hanged down at a depth of six meters in the sea for a period of one year. Identification of the organisms obtained from wood panels revealed the presence of five wood borer and 26 fouling species. Iskenderun harbour had the highest boring organism diversity (five species) and it was followed by Trabzon and Finike harbours (three species) and Bandirma, Eregli and Alacati harbours (two species). The two molluscan boring species, Teredo navalis and Lyrodus pedicellatus were observed at all harbour sites, but Nototeredo norvegica was at Trabzon and Iskenderun harbours only. Bankia carinata was obtained only at Iskenderun harbour and the crustacean wood borer Limnoria tripunctata was found at Finike and Iskenderun harbours. All native tree species, except for the olive, were significantly damaged by fouling and boring organisms.