Objective To analyze the differences of socio-economic characteristics, risk factors and TOAST subtype between very old patients and old patients with first-ever ischemic stroke (IS). Methods A total of 858 very old patients and 3818 old patients in CNSR were collected from September 2007 to August 2008. Demographic and socio-economic characteristics included age, gender, marital status, living condition, educational level, family income and health insurance types. Risk factors, including hypertension (HT), obesity, coronary heart disease (CAD), diabetes mellitus (DM), atrial fibrillation (AF), smoking, family history of stroke, hyperlipidemia, heavy drinking and so on, were analyzed. Results Compared with old group, significant differences were observed in very old group in demographic and socio-economic characteristics such as average age, gender, marriage, living conditions, educational levels and medical insurance(P＜0.05) except for monthly family income. Both two groups had the highest prevalence of HT. The rate of AF in very old group were higher than that in old group (P = 0.0002). However, very old patients were less likely to have metabolic disorders such as obesity(P = 0.0177), DM(P＜0.0001), hyperlipidemia(P＜0.0001) or bad behaviors such as smoking(P＜0.0001) and heavy drinking(P = 0.0004) compared with old patients. Cardiac embolism(CE) was significantly higher in very old patients(P＜0.0001). Conclusion There are differences on gender distribution and risk factors between old stroke patients below 80 and over 80 years. For very old patients, we should pay more attention to the risk of stroke in women and improve the understanding of AF and CE, so as to reduce the risk of recurrent stroke.