This is the first study of free-living heterotrophic flagellates in intertidal sediments of Saros Bay, Aegean Sea (Turkey). In order to contribute to an understanding of the geographic distribution of free-living marine heterotrophic flagellates, we investigated the diversity of heterotrophic flagellates occurring in the bay from 25th June 2010 to 10th October 2010. Thirty eight species from 30 genera of heterotrophic flagellates and one unidentifi ed taxon are reported with uninterpreted records based on light-microscopy. The records consist of one apusomonad, one cercomonad, two choanofl agellates, two cryptomonads, 12 euglenids, one heteroloboseid, one kathablepharid, three kinetoplastids, six stramenopiles, two thaumatomonads and seven of uncertain affinities. All of the morphospecies described here was previously reported elsewhere and appear to be cosmopolitan.