Genetic risk factors play an important role in the aetiology of vascular diseases. The insertion/deletion polymorphism (4G/5G) in the promotor region of the plasminogen activator inhibitor 1 (PAI-1) gene has been associated with an increased risk of myocardial infarction. We investigated 136 patients with minor stroke (MS) and transient ischaemic attack (TIA) and found a prevalence of 0.32 for the 4G/4G genotype in patients compared with 0.42 in 115 age-matched healthy controls. The 4G/4G genotype was significantly less frequent among 61 patients symptomatic before the age of 60 years (prevalence 0.20) than in 75 patients symptomatic after 60 years of age (prevalence 0.42; odds ratio). Our results indicate that the 4G/4G genotype is not a risk factor for MS or TIA and may even be protective in young patients.