This study was carried out in order to determine population of Zooplankton in the coastal waters of Gökçeada. At the 10 stations of those depths ranging from 20 m to 30 m, the measurements of temperature, salinity and oxygen were made, and Zooplankton samples were collected vertically and horizontally using plankton nets. In the neritic waters of the island, the effects of the Black Sea waters through Dardanelles were observed and Zooplankton species of the Black Sea found. From laboratory examinations of samples, it was determined that the most important group of Zooplankton was copepods. The number of Mnemiopsis leidyi, ctenophor, increased excessively during the periods of summer and autumn. Larger copepod species, such as Centropages typicus, Calanus helgolandicus, Clenocalanus vanus, Anomalocera patersoni, appeared during winter and spring periods; however, Acartia dausi, which is considered as a indicator of polluted waters, was found to be abundant at every station all around the year. Relatively smaller species such as Corycella fostrata, Oithona helgolandica, Euterpina acutifrons were determined in smalles numbers at most stations. Cladocers were observed at every period: of them, 'Penilia avirostris was found to be the most observed species. In (he samples collected from 40 stations during the year, 51 species were determined.