Objective To explore the risk factors for epilepsy associated with ischemic stroke in order to strengthen the early prevention, guide clinical treatment and improve prognosis. Methods One hundred and one patients with epilepsy associated with ischemic stroke within 24 hours and 101 ischemic stroke patients without epilepsy were randomly treated in Tianjin Huanhu Hospital from May 2007 to January 2009. According to the development of seizures they were divided into 2 groups: epilepsy group and stroke group. The score of clinical neurologic function deficiency was assessed according to the Scandinavian Stroke Scale (SSS) at the time of admission. All the patients accepted computerized tomography (CT) or magnetic resonance imaging (MRI) within 48 h after onset. Recorded age, gender, past history which included hypertension, coronary heart disease, atrial fibrillation, Type Ⅱ diabetes and hyperlipidemia, serum electrolyte (potassium ion, sodium ion and chloridion), disease status (quiet or active), ischemic stroke subtype which included atherosclerotic thrombotic cerebral infarction, cerebral embolism and lacunar infarct, angiorrhea after cerebral infarction, affected lobar or basal ganglia, affected hemisphere (left, right or bilateral), brain atrophy, white matter demyelination and neurological deficit scores. Unconditional multivariate Logistic regression analysis was performed for those factors which were significant after univariate analysis. Results The univariate analysis on epilepsy group and stroke group showed that significant differences in ischemic stroke subtype (cerebral embolism), angiorrhea after cerebral infarction, lesion location, especially affected frontal which achieved 48.72%, affected right hemisphere and neurological deficit scores (the SSS) were seen between the two groups (P ≤ 0.05, for all). Age, gender, past history which included hypertension, coronary heart disease, atrial fibrillation, diabetes and hyperlipidemia, serum electrolyte (potassium ion, sodium ion and chloridion), disease status (quiet or active), brain atrophy and white matter demyelination presented no significant differences (P > 0.05, for all). In unconditional multivariate Logistic regression analysis, cerebral embolism (OR = 0.152, 95% CI: 0.065-0.496; P = 0.011), angiorrhea after cerebral infarction (OR = 0.105, 95% CI: 0.020-0.549; P = 0.008), lobar cortical location (OR = 0.099, 95%CI:0.044-0.225; P = 0.000) and the SSS < 30 (OR = 0.145, 95%CI: 0.062-0.337; P = 0.000) were the main risk factors for epilepsy associated with ischemic stroke, whereas, affected right hemisphere (OR = 0.638, 95%CI: 0.311-1.308; P = 0.220) may not increase the probability of epilepsy associated with ischemic stroke. Conclusion Ischemic stroke patients who have cerebral embolism, angiorrhea after cerebral infarction, cortical location (especially affected frontal), the SSS < 30 are prone to develop epilepsy associated with ischemic stroke. DOI:10.3969/j.issn.1672-6731.2010.02.016