Stroke is the leading cause of long-term adult disability and the fifth leading cause of death in the US, with approximately 795,000 stroke events annually. The aging population and reduced case fatality are expected to increase the prevalence of stroke by 3.4 million people between 2012 and 2030. While stroke mortality has decreased over the past two decades, recent trends indicate a possible leveling off or even a rise in mortality, possibly due to the obesity epidemic and associated diabetes. The morbidity associated with stroke remains high, with costs estimated at $34 billion per year for healthcare services, medications, and lost work days. Subclinical cerebrovascular disease, including silent infarction and ischemic white matter disease, is also associated with significant functional disability. Stroke is divided into hemorrhagic and ischemic types, with the majority (about 80%) being ischemic. Risk factors for hemorrhagic and ischemic strokes are similar but differ among etiologic categories. Hypertension is a critical risk factor for hemorrhagic stroke, while hyperlipidemia is a key factor for atherosclerotic ischemic strokes. Atrial fibrillation is a significant risk factor for cardioembolic strokes. The epidemiological transition from hypertensive hemorrhagic stroke to ischemic strokes has been observed in developing countries, where hypertension is more prevalent. Risk factors for stroke include both modifiable (e.g., diet, comorbid conditions) and non-modifiable (e.g., age, race) factors. Risk scoring systems, such as the Framingham Stroke Risk Profile, help estimate 10-year stroke risk and guide preventive strategies. Non-modifiable risk factors for stroke include age, sex, race-ethnicity, and genetics. Stroke incidence increases with age, and women have a higher risk at younger ages due to hormonal factors. Racial disparities in stroke incidence and mortality are significant, with African Americans and Hispanic/Latino Americans at higher risk. Genetic factors, such as parental history and family history, also increase stroke risk. Modifiable risk factors are crucial for reducing stroke risk. Hypertension is the most important modifiable risk factor, with a strong, direct relationship between blood pressure and stroke risk. Diabetes, atrial fibrillation, dyslipidemia, sedentary behavior, diet, obesity, and metabolic syndrome are also significant risk factors. Alcohol consumption, substance abuse, smoking, and inflammation from infections or air pollution can trigger strokes. Genetic factors, such as rare single-gene disorders and common genetic polymorphisms, contribute to stroke risk through various mechanisms. Heritability estimates for different stroke subtypes vary, and certain single-gene disorders, like CADASIL, CARASIL, and Fabry disease, can lead to stroke as a primary manifestation. Emerging evidence suggests that genetics play a role in common ischemic stroke risk factors, with several genetic variants identified but having a modest effect.Stroke is the leading cause of long-term adult disability and the fifth leading cause of death in the US, with approximately 795,000 stroke events annually. The aging population and reduced case fatality are expected to increase the prevalence of stroke by 3.4 million people between 2012 and 2030. While stroke mortality has decreased over the past two decades, recent trends indicate a possible leveling off or even a rise in mortality, possibly due to the obesity epidemic and associated diabetes. The morbidity associated with stroke remains high, with costs estimated at $34 billion per year for healthcare services, medications, and lost work days. Subclinical cerebrovascular disease, including silent infarction and ischemic white matter disease, is also associated with significant functional disability. Stroke is divided into hemorrhagic and ischemic types, with the majority (about 80%) being ischemic. Risk factors for hemorrhagic and ischemic strokes are similar but differ among etiologic categories. Hypertension is a critical risk factor for hemorrhagic stroke, while hyperlipidemia is a key factor for atherosclerotic ischemic strokes. Atrial fibrillation is a significant risk factor for cardioembolic strokes. The epidemiological transition from hypertensive hemorrhagic stroke to ischemic strokes has been observed in developing countries, where hypertension is more prevalent. Risk factors for stroke include both modifiable (e.g., diet, comorbid conditions) and non-modifiable (e.g., age, race) factors. Risk scoring systems, such as the Framingham Stroke Risk Profile, help estimate 10-year stroke risk and guide preventive strategies. Non-modifiable risk factors for stroke include age, sex, race-ethnicity, and genetics. Stroke incidence increases with age, and women have a higher risk at younger ages due to hormonal factors. Racial disparities in stroke incidence and mortality are significant, with African Americans and Hispanic/Latino Americans at higher risk. Genetic factors, such as parental history and family history, also increase stroke risk. Modifiable risk factors are crucial for reducing stroke risk. Hypertension is the most important modifiable risk factor, with a strong, direct relationship between blood pressure and stroke risk. Diabetes, atrial fibrillation, dyslipidemia, sedentary behavior, diet, obesity, and metabolic syndrome are also significant risk factors. Alcohol consumption, substance abuse, smoking, and inflammation from infections or air pollution can trigger strokes. Genetic factors, such as rare single-gene disorders and common genetic polymorphisms, contribute to stroke risk through various mechanisms. Heritability estimates for different stroke subtypes vary, and certain single-gene disorders, like CADASIL, CARASIL, and Fabry disease, can lead to stroke as a primary manifestation. Emerging evidence suggests that genetics play a role in common ischemic stroke risk factors, with several genetic variants identified but having a modest effect.