Background and Purpose: The purpose of this study was to determine the incidence and risk factor of ischemic stroke subtypes by a mechanismbased classification scheme (Trial of ORG 10172 in Acute Stroke Treatment [TOAST]). Materials and Methods: This study was conducted in Indraprastha Apollo Hospital, New Delhi, between 01/01/2004 and 31/12/2006. Out of 361 admitted stroke patients, 244 (67.59%) ischemic stroke patients were analyzed retrospectively for incidence and modifiable risk factors for stroke in our region. The cause of ischemic stroke was classified according to the TOAST criteria. Results: Out of 244 patients 165 (67.6%) were male and 79 (32.4%) were female, the mean age at the time of stroke was 57.1 years, the incidence of different risk factors were as follows: 139 (56.9%, odds ratio 2.71) hypertensive, 85 (34.8%, odds ratio 2.4) diabetics, 95 (38.9%, odds ratio 3.12) smokers, 58 (23.7%, odds ratio 5.34) dyslipidemics, 44 (18.0%, odds ratio 1.43) coronary artery disease (CAD) patients, 14 (5.7%, odds ratio 1.22) patients have the transient ischemic stroke in the past, 13 (5.3%, odds ratio 1.43) were given the history of atrial fibrillation. The incidence rates of ischemic stroke subtypes were as follows: Determined causes; large artery atherosclerosis 141 (57.7%), lacunes 18 (7.7%), cardio-embolism 11 (4.5%), hypercoagulable state 8 (3.2%), un-determined causes; atherosclerosis and/or lacunes 25 (10.2%), embolism and/or two more (hypercoagulable state/CAD) possible causes 7 (2.8%), negative evaluation in 34 (13.9%) patients. Ischemic stroke subtype according to the TOAST criteria was a significant predictor for long-term survival. Conclusions: Our data indicate that large vessel disease is a major cause, and the hypertension, diabetes, smoking, hyperlipidemia are the most common risk factors for Ischemic stroke.