Rheumatoid arthritis (RA) is an autoimmune disorder, occurs when there are attacks of the immune system on body’s tissues especially the joint, causing a painful, swelling, that finally results in bone deformity, increased free radical level in defect joint and reduce the level of the antioxidant system can cause tissue damage. Serum levels of lipid peroxides, calcium, phosphorus and ratio of calcium/phosphorus in RA patients were determined and compared with normal healthy controls. Significant increases in lipid peroxides (p<0.001) phosphorus (p<0.001) levels were found in patients presenting with RA as compared to controls. Whereas significant decrease in calcium (P<0.001) and calcium/phosphorus ratio (p<0.001) were found in Rheumatoid arthritis patients as compared to controls. Negative correlation was observed between MDA and Calcium/Phosphorus ratio in patients with rheumatoid arthritis. Our findings suggest that there is a close association between bone loss and oxidative threat in patients presenting with Rheumatoid arthritis. The decrease in serum calcium / phosphorus ratio indicated that, calcium and phosphorus metabolism is altered in RA. Ca and P level can be studied for the preferabletherapeutic management of RA.