Introduction: Osteoarthritis is the most common degenerative chronic joint condition and the most common cause for the physical inability among elderly. One of the possible treatment procedures for osteoarthritis is pulsed electromagnetic therapy which encourages tissue repair using electromagnetic fields. Purpose: The main purpose of this thesis was to review randomized controlled trials in order to establish the effects of magnetotherapy in patients with knee osteoarthritis. Methods: Trials were identified through databases: PEDro, PubMed, CINAHL, Science Direct and Cochrane library. We included studies published between years 2005 and 2017. Results: The review included ten randomized controlled trials. Studies differentiated in patients participated, type of devices used, duration of each therapy and the total number of therapies. Effectiveness of the therapy was assessed with following measurements, visual analog scale for pain assesment, Western Ontario and McMaster University Osteoarthritis index, knee injury osteoarthritis outcome score, Lequesne index stage of knee osteoarthritis and Likert scale of severity of pain. Authors confirmed the effectiveness of magnetotherapy in six studies and in four studies it was not confirmed. Long term effects of magnetotherapy were confirmed in three studies. In studies in which magnetotherapy was added to other procedures there was no added effect from magnetotherapy in treatment. Discussion and conclusion: Magnetotherapy was shown as effective in most of the studies in pain relief and improvement in function. There is inconclusive evidence on the most effective way for the use of magnetotherapy, nor evidence about possible effectiveness of it on inflammatory processes and quality of life. Further studies should focus more on exploring the effectiveness on other processes in the osteoarthritic knee joint and on effect on the individual in everyday life.