We describe 3 relatively young patients who developed arterial occlusions in a limb requiring amputation. All 3 had antiphospholipid antibodies (APLA). In one, these appeared as part of the clinical and serologic spectrum of systemic lupus erythematosus and in the other 2 as a component of a primary antiphospholipid syndrome. Their arterial angiograms showed gradual narrowing of the arterial lumen and the histopathologic study showed striking intimal and medial proliferation as well as some increase in thickness of the adventitia. There was little evidence of thrombosis but in the 2 patients who were amputated early there was mononuclear cell infiltrate of the large arteries and in all 3 there was also leukocytoclastic vasculitis in the skin and/or muscle. We believe this represents a new form of vasculopathy, probably related to the presence of APLA, possibly triggered by the occurrence of vasculitis.