Effects of balneotherapy on gait properties of patients with osteoarthritis of the knee were investigated prospectively. A total of 30 patients with knee osteoarthritis received balneotherapy consisting of two daily thermomineral water baths for 2 weeks. Patients were evaluated using gait analysis and clinical scores, both within 2 weeks, before and after spa treatment. Patients were walking faster in their control analyses (0.81 +/- 0.21 to 0.89 +/- 0.19 m/s; P = 0.017), with a shorter mean stance time (63.0 +/- 3.3 to 61.8 +/- 2.5% stride; P = 0.007), an increased cadence (96 +/- 13.1 to 100 +/- 11.9 steps/min; P = 0.094) and stride length (996 +/- 174 to 1,058 +/- 142 mm; P = 0.017). Balneotherapy also resulted in a significant decrease in Lequesne knee osteoarthritis index (12.1 +/- 3.7 to 10.0 +/- 3.3 points; P = 0.003), VAS for pain (58 +/- 25 to 33 +/- 15; P = 0.0001), VAS for patients' (56 +/- 24 to 29 +/- 19; P < 0.001) and investigator's global assessment (55 +/- 20 to 26 +/- 15; P < 0.0001) and WOMAC score (2.1 +/- 0.7 to 1.6 +/- 0.8; P = 0.0004). Balneotherapy has positive effects on gait properties and clinical health quality parameters of patients with knee osteoarthritis in short-term evaluations.