We describe a 35-year-old man with a history of previous deep vein thrombosis who presented with hypertension. Renal investigations revealed failure to excrete contrast medium by the right kidney on intravenous pyelography. Digital subtraction angiography showed an 80% stenosis of the left renal artery. He was antinuclear antibody negative, as well as negative for antibodies to double stranded deoxyribonucleic acid and extractable nuclear antigens. The lupus anticoagulant test and antibodies to cardiolipin were positive. He conforms to a diagnosis of "primary" antiphospholipid syndrome.