Fibrin D-dimer are the consequence of an excess of fibrinolysis. The raise of their level in coronary heart disease seems to be helpful to enhance the diagnosis of coronary ischemia. Prospective study over 4 months, including 22 patients (16 male, 6 female) divided in 2 subgroups: Group I: 10 patients investigated for stable angina Group II: 12 patients investigated for ACS without ST elevation. All patients underwent fibrin D-dimer dosage and coronarography. Fibrin D-dimer levels were higher in group II (924.5 ng/ml vs 703.9 ng/ml; p < 0.0001). In group II, 6 patients had ST depression with a level of fibrin D-dimer 879.5 ng/ml vs 969.6 ng/ml in the other 6 patients. We found a positive correlation between level of fibrin D-dimer and complexity of coronary lesions (1007 ng/ml in type C vs 675 ng/ml in type A lesions; p < 0.0001). Fibrin D-dimer seems highly implicated in coronary disease and if these results are confirmed by larger studies their routine dosage will be helpful in ACS.