This study reports Tinannopsis corniger Hada, 1964 for the first time from the Turkish coastal waters and contributes to the regional check-list of the plankton species in the Turkish seas. This species has generally been reported from the Japanese waters. It has also been reported from the Gulf of Mexico, the Atlantic Ocean, northern Mediterranean, Italy and Egypt. The specimens were collected in August and October 2010 from subsurface (0.5m) neritic waters in the Gulf of Gemlik, the Sea of Marmara. The primary hydrographic parameters, such as temperature (18-28 degrees C), salinity (16-18 ppt) and dissolved oxygen (7.96-13.10 mg l(-1)) were recorded at the sampling stations. Thirteen species belonging to genus Tintinnopsis were recorded from the Turkish seas with the contribution of this study.