Purpose: To investigate the levels of matrix metalloproteinase-9 in systemic lupus erythematosus patients and to determine its value in monitoring disease activity. Patients and Methods: Thirty systemic lupus erythematosus patients, 28 females and two males were included in this study, with fifteen age- and sex-matched volunteers serving as controls. The activity of SLE was evaluated according to SLAM score. Using quantitative ELISA technique kit provided from R&D system INC., USA, we quantitated the total levels of MMP-9. These levels were then compared and correlated with the patients' age, duration of illness, SLAM score, skin manifestations, lupus nephritis, neuropsychiatric manifestations, ANA, anti-ds-DNA, C3 and C4. Results: levels of MMP-9 were found to be significantly higher (P= 0.001), in SLE patients compared to the control group. However, serum levels of MMP-9 did not show any statistical significant correlation with the mentioned clinical and laboratory parameters. Conclusion: Although the levels of MMP-9 were found to be significantly higher in patients with SLE, yet it could not be tailored to any of the clinical features of the disease process nor its laboratory workup.