Khadjibey estuary is the estuary on the Black Sea coast and its located at 7 (9.5) kilometers by north-west of Odessa. The estuary length is about 31 km, width is 0.5-3.5 km (average – 2.5 km), square is about 70 km², depth is up to 15 m (average – up to 2.5 m). The salinity of the estuary is 5-6 parts per million. The estuary is separated from the sea by a sandy-shell recess, 5 km long and 4.5 km wide, and has no connection with the sea.

The estuary is a bay in the northwestern part of the Black Sea. It was formed by separation the mouth of the Small Kuyalnik River from the sea. The bottom of the Khadjibey estuary is covered with a layer of black mud, which has medicinal qualities. On this base Khadjibey resort was opened. A number of settlements are located on the bank of the estuary – Usatovo (there is a sanatorium “Khadjibey “), Great Balka, Cold Balka and summer cottages.

Khadjibey resort – one of the oldest mud resorts in the Russian Empire and the USSR; along with Kuyalnik resort, he was widely known in the first third of te 19th century.The main natural healing factors are mud and brine of the Khadjibey estuary. Compared with Kuyalnik, Khadjibey estuary is much more abundant, and the salt concentration of its brine is lower. On the chemical composition, the brine of Khadjibey estuary is chloride sodium-magnesium. The reserves of estuary mud are estimated at 13 million m³. It`s sulphide sludge mud and is widely used for mud therapy. On the shore of the estuary, a large sandy beach is used for climatotherapy. The resort also organizes the treatment of iodine-bromine and other baths, artificially prepared on the brine of the estuary; conduct physiotherapeutic procedures, physical therapy.

At the village Usatovo sanatorium ( 200 places) for children with diseases of the motion and support organs as well as with the consequences of certain diseases of the nervous system, water and mud baths are functioning. On the basis of the sanatorium – children’s neurological clinic of the Odessa Scientific Research Institute of Balneology is located.
The resort Cold Beam is also based on the mud of the estuary. Nowadays it is included in the structure of the Khadjibey resort as a building (complex) № 2. Complex number 3 of the resort “Khadzhibey” is located in Odessa at the address: Karkashadze Lane (Kirpichny), 2 (French Boulevard district, 2nd station of Bolshoi Fontan).

The so-called “reed” tram goes to the Khadjibey estuary (route № 20) – is another attraction of Odessa.