Balneotherapy (BT) is widely used in daily clinical practice for the management of osteoarthritis (OA) in many European countries, as well as in Turkey, Israel and Japan (OA). However, despite its long history and tradition, the scientific value of BT is still the subject of discussion. The aim of this overview was to discuss the current evidence and critical points about the mechanisms of action, clinical efficacy and costeffectiveness of BT in OA as well as the definition of the used term of "Balneotherapy". BT traditionally involves either immersion in mineral and/or thermal waters from natural springs and/or balneological interventions with natural gases or peloids (mud). The mechanisms of action of BT are not fully elucidated; the net benefit is probably the result of a combination of mechanical, thermal and chemical effects. Various randomized controlled clinical trials (RCTs) in patients with OA support a beneficial effect of BT on pain, function and quality of life that lasts over time after the treatment. Economic evaluations in this field are rare, however preliminary cost-effectiveness analysis have shown a favourable economic profile for BT in OA.