Problem. Taking into account rare occurrence of Ceratophyllum tanaiticum, present threat to the existence of its populations, it is very important to detect new locations of the plants and to protect them. Aim. To conduct floristic investigatiоns of water ecosystems of NNP “Biloberezhzhia Sviatoslava” and to give characteristics to a new location of C. tanaiticum. Methods. The location was detected after the examination by route method of two nameless lakes of Kinburn peninsula near the shore of the Dnieper estuary. Determination of this water plant was conducted by Determinant of Plants of Ukraine. Results. A new locality of C. tanaiticum was detected in two brackish-water nameless lakes of Kinburn peninsula on the territory of NNP “Biloberezhzhia Sviatoslava”. It was in compliance with the described in the literature biotopes characteristic for the species. The obtained results expand the information about the spread of C. Tanaiticum in Ukraine.