Objectives - To examine the relationship between atherosclerotic lesions of the middle cerebral artery (MCA) detected on MRA and vascular risk factors. Material and methods - We retrospectively assessed 279 patients (mean age, 69.0 + 11.3 years) who visited the Department of Neurology of Masuda Red Cross Hospital and underwent three-dimensional, time-of-flight MRA of the head between January 1996 and October 1998. Cases of cerebral embolism and internal carotid artery occlusion were excluded. Diagnoses were cerebral infarction (n= 152) and others (n= 127). We evaluated stenotic or occlusive lesions of the MCA (Ml portion), using MRA. Age, sex, history of hypertension, HbAlc, total cholesterol, fasting triglyceride, high density lipoprotein, lipoprotein(a), blood pressure, hematocrit, smoking and left ventricular hypertrophy (LVH) on ECG were included in the analysis. Results - 36 patients (12.9%) had stenotic or occlusive lesions of the MCA on MRA. Univariate analysis showed that age, hypertension and HbAlc were significantly correlated with MCA lesions. Multiple logistic regression analysis showed that HbAlC and hypertension were significant and independent predictors for MCA lesions. Conclusion - Hypertension and high serum HbAlc levels may contribute to the development of atherosclerotic lesions of the MCA in Japanese people.