Abstract Background: Osteoarthritis (OA) is a chronic degenerative joint disease, which commonly affects the knees. Aim of Study: To investigate if patients' age and BMI can predict patients' response to quadriceps muscle strength training on knee pain and the functional activity level in female patients with knee osteoarthritis. Patients and Methods: Forty female patients with The mean age of (54±8) years and The mean BMI of (33±5) kg/cm2, were referred by orthopedist diagnosed as knee osteoarthritis patient they all met the inclusion criteria then, Patients' personal data, age, body mass index, Knee pain intensity level and functional activity level all were recorded in patient evaluation sheet before applying quadriceps muscle strengthening exercise. Results: The patients' response to treatment was estimated by calculating the mean difference for pain intensity level (measured via VAS) and the function activity level (measured via 50 feet walk test & time up and go test). The correlation between results before and after Quadriceps muscle strength training exercise program was calculated. the results showed a significant difference between pre and post 50 feet walk test (56±12; 39±8 respectively), time up and go test (26±8; 18±6 respectively), pain intensity level (VAS) (7±1; 3.5±1.6 respectively), (p-value <0.05). Conclusion: Patients' age, BMI (height &weight) can be predictors of success for quadriceps muscle strength training exercise program in female patients with knee osteoarthritis.