We investigated whether impaired glucose tolerance (IGT) is a risk factor for stroke. The incidence of stroke and coronary heart disease (CHD) in a cohort population (n = 2,938) consisting of participants of the 1990-97 Funagata study was assessed through 2002. During the 147-months (mean 116.5 months) follow-up, 158(normal glucose tolerance (NGT), IGT, and diabetes: 94, 35, and 29, respectively) participants experienced a stroke, and 94 (54, 16, and 24, respectively) experienced CHD. By the person-year method, IGT was shown to be significant risk factors for stroke(odds ratio: 1.87, 95% CI: 1.73-2.03) and CHD(1.53, 1.31-1.78). Cox's proportional hazard analysis showed that IGT was a risk factor for stroke (age-, sex-, and hypertension-adjusted hazard ratio: 1.51, 95 % CI: 1.02-2.24, p = 0.039).