Osteoarthritis is one of the degenerative diseases and Low level laser therapy (LLLT) has been prescribed as nonoperative treatment in physiotherapy. But the available evidences of finding the radiological and biochemical effectiveness of LLLT are very few. So, the purpose of this study is to find the radiological and biochemical effect of Low level laser therapy (LLLT) in the treatment of Osteoarthritis. 34 subjects who fulfilled the inclusion and exclusion criteria were divided into two groups (Active Laser group – ALG & Placebo Laser group - PLG) with randomized sampling method. ALG was treated with active laser head, whereas PLG treated same like ALG but without emission of energy. Both groups were applied with kinesio tape for 4 weeks. The frequency of the treatment was three times per week for 4 weeks in both groups. Subjects were assessed at baseline, 4th and 8th week. Contact area (mm2) – medial & lateral and cartilage thickness (percentage) - medial & lateral was measured by Magnetic resonance image (MRI) and CTX-II (μmg/mmol) was measured by urine analysis. A statistically significant (p ≤ 0.05) difference between both groups were noted at the period of 8 week for contact area (lateral) and CTX-II and insignificant (p ≥ 0.05) difference in contact area (medial) and cartilage thickness (medial & lateral) were noted. In conclusion, the low level laser therapy is helpful in modifying the biochemical components and leads to make changes in the cartilage which subsequently improve the quality of life of OA patients.