Multifocal small low-signal lesions on T2*-weighted gradient-echo (GE) MRI are reported to be common in the brain of hypertensive patients. We examined factors associated with these lesions. For one year, we routinely obtained T2*-weighted GE images (TR 1000 TE 30 ms, flip angle = 20 degrees) in all adult patients (314) who underwent brain MRI in our hospital, using a 1.5 T superconducting magnet. Patients with multifocal small low-signal lesions with a known or presumed pathogenesis or any condition which may cause intracerebral haemorrhage, such as brain tumours, were excluded from further analysis. Thus, 191 cases remained (104 men and 87 women; age, 62.8+/-11.0 years, range, 30-89 years). The overall prevalence of multifocal small low-signal lesions on the GE images was 15.2% (29/191); they were commonly in the cerebral white matter and basal ganglia. They were detected in 12 (52.2%) of the 23 patients with prior symptomatic brain hemorrhage, 12 (20.7%) of the 58 with prior symptomatic infarcts, and only five (4.5%) of 110 without a prior stroke. Logistic regression analysis indicated that multifocal small low-signal lesions were significantly correlated with a symptomatic acute brain haemorrhage (odds ratio, 13.17), chronic hypertension (4.00) and a symptomatic acute infarct (3.71). The association with symptomatic acute brain haemorrhage suggests that this finding may represent subclinical microhaemorrhage. The diagnostic potential of this finding to identify individuals at risk of symptomatic intracerebral haemorrhage may require further investigation.