Background: We conducted a prospective study to determine the prevalence of activated protein C resistance and anticardiolipin antibodies in leg ulcers, whatever venous, arterial or arteriovenous., Patients and Methods: One hundred fifteen patients hospitalized for leg ulcers, without antiphospholipid syndrome were included. The vascular abnormalities were studied by clinical examination, Doppler, duplex Doppler and, when required, arteriography. Activated protein C resistance was isolated by a "classic" test (normalized APTT ratio in PCa presence or absence) and by a "second generation test" (by preliminary dilution with deficient factor V plasma). All patients with abnormal results on the second test were screened for the factor V Leiden (by PCR amplication with use of restriction enzymes). Anticardiolipin antibodies were investigated with an ELISA method with Harris standards as reference, in which the positive threshold was established at 20 units., Results: Among these 115 patients, 50 venous (43.5 p. 100), 23 arterial (20 p. 100), 42 arteriovenous (36.5 p. 100) leg ulcers were identified. Activated protein C resistance was isolated in 12 cases (10.4 p. 100) (heterozygous carriers): 7 venous ulcers, 3 arteriovenous, 2 arterial. Anticardiolipin antibodies were measured at significant level in 49 cases (42.6 p. 100): 21 venous ulcers, 18 arteriovenous, 10 arterial., Discussion: In this study, there was no statistical difference between the activated protein C resistance prevalence in leg ulcers when compared with Lorraine population (p=0.27). Factor V Leiden or anticardiolipin antibodies abnormalities were isolated in 56 cases (48.7 p. 100) without statistical difference between the 3 types of ulcers. Finally, the pathophysiology of venous, arterial and arteriovenous leg ulcers remains complex, suggesting several coagulation perturbations.