This research was carried out to determine the invertebrate fauna associated with Cystoseira barbata facies distributed in the upper-infralittoral zone of the Southeastern Black Sea coasts and their bioecological features. The investigations were seasonally performed at depths of 0 to 3 m in 5 different stations chosen in the Southeastern Black Sea from July 2005 to May 2006. As a result of the study, a total of 6123 specimens belonging to 38 species and 4 taxonomic groups were identified. Arthropoda was the dominant group in terms of number of species (55.3% of the total of phylum) and number of individuals (83.9% of the number total individuals). With regard to frequency index, 14 species were defined as continious, 8 species of common and 16 species as rare. Idotea metallica is reported for the first time from the Black Sea coast of Turkey in the present study.