Many Ponto-Caspian invertebrate species have been introduced to new areas in Europe, Baltic Sea and North America. In Turkey, the Ponto-Caspian fauna has spread in the inland waters, following different patterns and in different geological periods. Lake Sapanca is located on a tectonic hole in the Marmara region in the north-western part of Turkey. Except for a few studies, there has been no detailed information about the non-indigenous and Ponto-Caspian species in the lake. In the present study (from June 2011 to December 2013), the benthic macroinvertebrate fauna of Lake Sapanca was determined. The following Gastropoda species, which originate from the Ponto-Caspian area, were detected: Lithoglyphus naticoides, Esperiana esperi, and Borysthenia naticina. The presence of these species in different parts of Turkey suggests that the main routes of migration might be the rivers flowing into the Black Sea. Some notes on the Ponto-Caspian and invasive Clitellata species in the lake were made.