The aim of this study was to determine the environmental factors affecting distribution and diversity of ostracods (Crustacea: Ostracoda) in the inland waters of the northern Aegean Sea island of Gokceada (Imbros), Turkey. Over a period of one year, sampling of ostracods was performed in order to estimate the composition, richness, and diversity of the ostracod assemblages from the Gokceada Island. A total of 18 ostracod species were identified from 28 sampling sites during the course of the study. In both winter and summer seasons, Heterocypris salina (Brady, 1868) and Cyprideis torosa (Jones, 1850) were the most abundant species. Heterocypris salina and Ilyocypris gibba (Ramdohr, 1808), were the most common species. The total number of ostracods was highest in the summer (June). During the study, the freshwater temperature varied between 10 and 29 degrees C, while salinity varied between 0.1 and 41.4%; the values of pH and dissolved oxygen ranged from 7.1 to 8.4 and 5.4 to 7.9 mg L-1, respectively. The diversity of the ostracods was calculated using the Shannon-Weaver diversity index. The highest diversity (H' = 3.427) was at macrophyte-rich sampling site 8, the lowest diversity (H' = 0) was at macrophyte-poor sites 15, 17, 19, and 22. The numbers of cosmopolitan (10 species) and widespread ostracods (2 species) were higher than those of non-cosmopolitans. A close relationship exists between distribution of ostracod species and the physicochemical features of waters and typology of water resources, considering that most of the water resources on the island are fountains and their troughs and that their waters have similar physicochemical properties.