Background: Acute lung injury (ALI) is a syndrome with a diagnostic criteria based on hypoxemia and a classical radiological appearance, with acute respiratory distress syndrome at the severe end of the disease. Facts recommended the occurrence of rupture of the basement membranes and interstitial matrix remodeling during ALI. Matrix metalloproteinase (MMPs) participate in tissue remodeling related with pathological conditions such as acute lung injury. We hypothesized the interrelationships between extracellular matrix (ECM) turnover as MMP-9 and indicator of angiogenesis such as angiopoietin-2 (Ang-2) as well as plasma von Willebrand factor (vWF) and their correlation with arterial partial pressure of oxygen (PaO2), oxygen saturation (SaO2) and mortality in ALI/ARDS. Materials and Methods: 88 mechanically ventilated patients [68 male, mean (SD) age 61 (10) years] were compared to 40 healthy controls [36 male, mean (SD) age 57 (10)]. All biomarkers were measured by Enzyme linked immunosorbeant assay (ELISA). Oxygenation, body temperature, leucocytes, and platelet counts were noted. Results: Plasma levels of all biomarkers were significantly different, among ALI/ARDS subjects (p<0.001). They were inversely related to PaO2 and SaO2and positively related to mortality. In addition, increased MMP-9, Ang-2 and vWF levels were interrelated on the first day of admission. Conclusions: The observed diversity in plasma levels of MMP-9, Ang-2 and vWF in ALI/ARDS patients revealed the activity and severity of the disease, shedding more light onto the pathogenesis and/or presentation of ARDS.