Аннотация:Diversity and distribution of free-living benthic ciliates were studied at eight localities at the north-eastern (Caucasian) coast of the Black Sea, at the depths from 0 to 432 m. The highest diversity was revealed in the heterogeneous sublittoral sands at 3-10 m depths, the lowest one, at exposed littoral beaches with well-sorted coarse sands and in the silty sediments deeper than 25 m. No ciliates were found in the hydrosulphuric zone (below 100 m). With increasing depth, raptorial feeders became relatively more diverse, while the proportion of down-steam filter feeders decreased. On the basis of species composition, several communities were distinguished corresponding to depth range and sediment properties. Point diversity of ciliates (defined as number of species per sample) depends mainly on local habitat conditions (depth and sediment properties), under similar conditions its variations between regions are insignificant. Local diversity (total number of species found at a site) depends strongly on sampling effort and is potentially comparable with that of larger areas.