Arthrosis (osteoarthritis) is the most common disease affecting synovial joints characterized with degenerative and progressive course. Gonarthrosis most commonly occurs beetwen 40 and 60 years and may be primary and secondary. There are numerous factors that contribute to the formation of gonarthrosis and some of them are age, gender, genu valgum or genu varum deformity, knee trauma, inflammatory joint disease, muscle imbalance, hereditary factors and obesity. Gonarthrosis is characterized with typical signs and symptoms such as pain, swelling, joint stiffness and muscle weakness which impairs the quality of life of patients. Treatment of gonarthrosis can be conservative, medical and surgical. Physiotherapy has a major role in conservative treatment. Physiotherapeutic interventions that are used include cryotherapy, termotherapy, ultrasound therapy, laser therapy, hydrotherapy, kinesio taping, magnetotherapy, electrotherapy, assistive device use, patient eduaction and movement therapy. Also alternative and new methods such as Tai Chi, Ai Chi, acupuncture and whole body vibrations are increasingly being applied. If conservative treatment is not successful, surgical treatment is being applied (surgical osteotomy and implantation of total joint endoprosthesis).