Objective: The main goal of this study was to compare two modalities of non-pharmacological treatment for knee osteoarthritis (OA) in patients older than 70 years. The evaluation considered the reduction of pain and improvement of function ability. Methods: The study included 80 patients that met ACR (American Colledge of Rheumatology) criteria for the knee OA diagnosis. The patients were divided in two groups and in a control group. All patients had X-ray scans of the knee joint and the stage of knee osteoarthritis was graduated using the Kellgren-Lawrence (K-L) scale. Group ”A” consisted of 30 patients who were treated with High Intensity Laser Therapy (HILT). In group ”B” there were 30 patients treated with interferential current. Patients the the control group C (20) did not undergo any electrotherapy. Patients from all three groups had cryotherapy and medical exercises. Duration of treatment was ten days. The evaluation of the patients” condition was done at the beginning and at the end of the prescribed therapy. Specific test, Visual analog scale (VAS) and the Lequesne functional index (LFI) were given for testing the efficiency of those therapies, before and after therapy. Results: The results were analyzed using a programme for statistical processing of the gathered data Statistica 9.1. (StatSoft Inc., Tulsa, USA) and SPSS subdivision 16.0 (SPSS Inc., Chicago, IL, USA). The level of significance was determined by the criteria value of the parameter P 0.05. Regarding the gender, affected side and the stages of OA, there are no statistically significant differences found among the groups. At the end of the treatment patients in group A (HILT) had a statistically significantly greater analgesic efficiency (VAS scale) compared to patients in the control group C (P = 0.009), and to patients in group B treated with IF current (P = 0.035). LFI after treatment was significantly the lowest in group A patients, who received HILT (<0.001). Discussion: Treatment of the knee OA is complex and multimodal. The results of our study have shown a statistically significant greater analgesic efficiency and functional improvement in patients treated with HILT compared to patients treated with IF current, in the group of elderly patients with the knee OA. Conclusion: In physical therapy of the knee OA we find that the application of HILT is a reliable and efficient option.