Part of the famous Hotel Gellért in Buda, the Gellért Thermal Baths and Swimming Pool, also known simply as the Gellért Baths, is a bath complex in Budapest in Hungary.

The Gellért Baths complex includes thermal baths, which are small pools containing water from Gellért hill’s mineral hot springs. The water contains calcium, magnesium, hydrocarbonate, alkalis, chloride, sulfate, and fluoride. Medical indications of the water includes degenerative joint illnesses, spine problems, chronic and sub-acute joint inflammations, vertebral disk problems, neuralgia, vasoconstriction and circulatory disturbances; inhalation problems for the treatment of asthma and chronic bronchitis problems. The temperature of the water is between 35 °C and 40 °C.The thermal baths are decorated beautifully with mosaic tiles.

Gellért Spa is famous for its main hall with gallery and glass roof, built in Art-Nouveau style. The complex also includes saunas and plunge pools (segregated by gender), an open-air swimming pool which can create artificial waves every 30 minutes and an effervescent swimming pool. A Finnish sauna with cold pool is also enclosed within the complex. Masseuse services are available.

Gellért Baths also offer a range of medical services. Towels and swimsuits may be rented or bought in the Spa. On holidays and at weekends the entrance fee is higher than on workdays. In June 2014, the prices were between 4900 and 5100 HUF. Massage is charged extra (4400 HUF for a basic massage).