Objectives: Stromelysin (MMP-3) production is increased in rheumatoid arthritis (RA), the present study was aimed to evaluate the level of MMP-3 in RA sera, and to detect its relation with ongoing disease activity in RA patients.Methods: The study group included 40 RA patients satisfying the ACR criteria of diagnosis, and 10 healthy subjects, who served as controls. Serum levels of Matrix metalloproteinase-3 was measured using ELISA technique.Results: Serum MMP-3 levels were higher in serum of patients with RA than in normal controls, and they correlated significantly with ESR, TCL and CRP. Also, a statistically significant correlation was found with Modified Larsen score, and disease activity as measured by DAS28 score.Conclusion: Serum MMP-3 may therefore be a measurable ,useful, and a specific marker of active RA.