Abstract Background: Osteoarthritis (OA) of the knees can affect the muscle function and functional performance of the sur-rounding muscles. Aim of Study: We aimed to investigate the concentric torque, total work and average power of knee muscles (quadri-ceps and hamstring) and functional status in OA patients in comparison with a matched control group. Patients and Methods: This cross-sectional study included patients with grade II knee OA diagnosed clinically according to the American College of Rheumatology (ACR) criteria and who had radiographic evidence of grade I or II tibiofemoral OA as judged by the Kellgren and Lawrence scale and 30 matched healthy individuals. Pain, stiffness, and physical function were assessed using visual analogue scale (VAS), Western Ontario and McMaster University Arthritis Index (WOMAC) and timed walking test. Muscle strength was measured using a comput-er-driven isokinetic dynamometer. The isokinetic variables used in the statistical analysis were peak torque, total work, and average power. Results: This study was conducted on thirty patients (21 fe-males and 9 males) with mean age 44.967±4.238 diagnosed as knee osteoarthritis and 30 matched healthy subjects with mean age 46.067±3.741 and p-value was 0.362. The control group and the group of patients with knee OA were matched for gen-der and age. The independent t-test revealed statistically signif-icant differences between the two groups with regard to isoki-netic concentric peak torque, total work and average power at different angular velocities and for the timed walking test, as a measure of functional status. However, no significant differ-ence in lower extremity joints' ROM and thigh girth were seen. Conclusion: Patients with knee OA, even in low grades and with minimum symptoms and signs, had muscle weakness and functional limitation in comparison with the matched healthy subjects.