Studies have reported that individuals with Rheumatoid Arthritis have a smaller muscle cross-sectional area, pennation angle and muscle thickness than healthy controls. Sarcopenia may decrease physical performance and quality of life in individuals with RA. Therefore, morphologic changes in the quadriceps femoris muscle due to sarcopenia may help us to gain insight into physical function and quality of life. This study aims to evaluate the predictive capacity of morphologic characteristics of the quadriceps femoris muscle for disease activity, physical performance, and quality of life in women with Rheumatoid Arthritis.