In the present study, the pattern of some extracellular matrix glycoproteins was determined in traumatic anterior cruciate ligament ruptures (n = 17) and in normal ligaments (n = 11). 6 mum cryo-sections were incubated with monoclonal antibodies recognizing tenascin, laminin, and fibronectin, and FITC-labeled secondary antibodies. Immunohistochemistry revealed that tenascin, fibronectin-and laminin are sparsely distributed in normal anterior cruciate ligaments, but strongly expressed in ruptured ligaments with a time-restricted pattern. The de novo-expression of tenascin appeared before laminin but later than fibronectin. The data suggest that fibronectin and tenascin are important, partially antagonistic components during healing processes after anterior cruciate ligament ruptures.