Circulating anticardiolipin antibodies are associated with recurrent thrombosis, fetal loss and thrombocytopenia. We have identified four patients with SLE or lupus-like disease who have high circulating levels of ACLA, repeated thrombosis and evidence of renal disease. Their clinical signs and symptoms of lupus activity were minimal, yet all had renal insufficiency with GFR 50 ml/min or less despite no history nor evidence of overt nephritis (proteinuria less than 0.5 g/day and no haematuria). Renal biopsy specimens showed focal ischaemic lesions with no evidence of active lupus nephritis. We describe a new lesion of renal ischaemia secondary to non-inflammatory vascular pathology associated with circulating ACLA.