We encountered three siblings (one female and two males) whose clinical manifestations were consistent with those of malignant hypertension (MH). Renal biopsies were obtained from two of the patients, and an autopsy from the third. The light microscopic findings from all three cases were characterised by marked intimal thickening with concentric layering of collagen and cellular proliferation in the interlobular arteries. Findings, on examination of optic fundi, including retinal haemorrhages, exudates and papilloedema were also consistent with malignant hypertension. The two male patients progressed to develop renal failure. These cases strongly suggest the existence of a rare familial form of primary malignant hypertension.