Phytal and intersititial harpacticoids inhabiting in the coasts which situated within the border of Balikesir province were determined in order to contribute the Turkish harpacticoid fauna. As a result, 37 species and 1 subspecies belonging to 33 genera distributed within 16 families were identified. Twenty four species and 1 subspecies were recorded for the first time from the Turkish seas. According to the species numbers, the families Diosaccidae and Ameiridae ranked first with 6 species, Paramesochridae and Laophontidae with 4 species, Ectinosomatidae and Tetragonicipitidae with 3 species, Harpacticidae and Tisbidae with 2 species, Longipediidae, Canuellidae, Thalestridae, Parastenheliidae, Metidae, Orthopsyllidae, Leptastacidae and Latiremidae with 1 species.