Background: There are limited data about Iyengar Yoga and EMG biofeedback in knee OA, although the efficacy of EMG biofeedback in the rehabilitation of patients with quadriceps muscle weakness secondary to immobilization, contracture, and joint surgery has been well established. Materials and Methods: Thirty subjects who have fulfilled inclusion and exclusion criteria were selected and divided into two groups (Group A and B). Both the groups were treated with EMG biofeedback, knee muscle strengthening exercises, and TENS. Group A received additionally Iyengar Yoga for 8 weeks. Both groups were evaluated by Visual Analog Scale and Modified WOMAC-Western Ontario McMaster Universities Scale. Results: Patients in both groups experienced significant reduction in pain and improvement in functional ability. In VAS scale Group A showed reduction of 56.83% ( P = 0.001) when compared with Group B 38.15% ( P ≤ 0.001). In modified WOMAC Scale, Group A showed reduction of 59.21% ( P = 0.001) when compared with Group B 34.08% ( P = 0.001). Conclusion : Adding Iyengar Yoga along with conventional therapy provides better results in chronic unilateral knee osteoarthritis in terms of pain and functional disability.