We describe 14 patients (mean age 57 years) in whom stroke or TIA was the presenting manifestation of a haematologic disorder. Twelve patients had an ischaemic stroke and 2 a haemorrhagic stroke. This group represented 1.27% (14/1,099) of the total number of patients with first-ever stroke diagnosed from 1986 to 1992 at our institution, accounted for 1.32% (12/906) of all brain infarcts and 1.03% (2/193) of all haemorrhagic strokes, and was the most common aetiology (25%) of ischaemic stroke of unusual cause. Haematological disorders included essential thrombocythaemia (6), polycythaemia vera (1), smoker’s polycythaemia (1), thrombotic thrombocytopenic purpura (1), IgA lambda myeloma (1), acute lymphoblastic leukaemia (1), Waldenström’s macroglobulinaemia (1), chronic granulocytic leukaemia (1) and IgG lambda myeloma (1). Stroke subtypes included definitive cerebral infarct (10), TIA (2), parenchymal haemorrhage (1) and spontaneous subdural haematoma (1). Vascular territories in ischaemic stroke were the carotid in 7 patients, the ver-tebrobasilar in 1 and undetermined in 4. Mean follow-up was 40 months (range, 1-96 months). The mortality rate was 1