Matrix metalloproteinesas (MMPs) are a major group of proteases that regulate cell matrix composition. They are produced by tissue structural cell including fibroblasts, endothelial cell and by inflammatory cells such as macrophages, neutrophils and eosinophil. Fifty asthmatic patients and twenty control subjects were included in this thesis. Following thorough history taking, clinical examination, pulmonary function test, sputum cytology for eosinophils and neutrophil, chest X ray and assay of serum matrix metelloproteineses-9 and tissue inhibitor metelloproteineses-1 were performed to the patients. Assay of serum matrix metelloproteineses-9 and tissue inhibitor metelloproteineses-1 were performed to the control subjects. Then, results were tabulated and statistically analyzed. MMP-9/TIMP-1 ratio was positively correlated with serum level of MMP-9 in all studied cases with statically significant difference.