The freshwater jellyfish Craspedacusta sowerbyi Lankester, 1880 (Cnidaria: Hydrozoa) has a worldwide distribution. It was seen in Sapanca Lake between early August and late September, 2009. C. sowerbyi was recorded in the eastern part of the lake. All individuals captured were with bell diameters ranging from 4-11.6 mm. Tentacle numbers ranged from 200 to 480.