The organismic assemblage associated with Caretta caretta was studied in 37 loggerhead turtles, washed ashore dead at various localities in the northern Aegean Sea. A total number of 63 macrobenthic species and 17 species of macroalgae were identified. From these species, 41 and 13 respectively are reported for the first time as epibionts of this turtle. Analysis of the epibiont species distribution on six loggerhead turtles gave some evidence regarding the settlement preferences of certain epibiont species. From a biogeographical point of view, 61·3% of the epibiont species were cosmopolitan, 30·7% had an Atlanto-Mediterranean distribution, while 8% were Mediterranean endemics.