Background: Osteoarthritis is the most common form of arthritis among adults, leading to substantial pain and disability. Aim: Evaluate the effect of quadriceps muscle strength exercise on the patients with osteoarthritis at Aswan university hospital. Research Design: is Quasi experimental. Subjects & Setting: A convenient sample of (60) newly diagnosed osteoarthritis of the knee joint adult patient recruited from the physical medicine department and rehabilitation department at Aswan university hospital divided into two groups study and control. Tools: two tools, tool onePatient's General Assessment Sheet; and The Knee Osteoarthritis Assessment checklist. Tool two is Algo functional for Knee Osteoarthritis Index (AKOI). Results: 76.7% of study and 60% of the control group were female. This study revealed statistically significant difference between study and control group of Knee Osteoarthritis Assessment post quadriceps muscle strength exercisesregarding complete flexion and complete extension of knee, p≤0.05. There was improvement in mean and S.D of pain in the study group than the control after applying the exercise at the 3^rd and 6^th week. Improvement in mean and SD between study and control group regarding all items of Maximum distance walked during follow up at 3^rd and 6^th week and p≤0.05. Conclusion: quadriceps muscle strength exercise effective in reduce pain and improve movement. Recommendations: Nurses should emphasis to provide a quadriceps muscle strength exercises on the patients with osteoarthritis.