Background Epilepsy is a common complication of pediatric stroke. Aim In this study, we aim to measure the association between epilepsy and neurologic outcome after childhood arterial ischemic stroke. Methods Prospective cohort study of children (29 days-19 years) enrolled after an acute arterial ischemic stroke at 21 international pediatric stroke centers and followed to identify epilepsy. One year post-stroke, outcomes were scored using the examination-based Pediatric Stroke Outcome Measure (range = 0-10); higher values reflect greater disability. Ordinal logistic regression was used to measure the association of Pediatric Stroke Outcome Measure scores (categorized as 0-1, 1.5-3, 3.5-6, 6.5-10) with epilepsy. Results Investigators enrolled 86 children (median age = 6.1 years, interquartile range (IQR) = 1.4-12.2 years) with acute stroke. At 1 year, 18/80 (23%) remained on an anticonvulsant including 8/80 (10%) with epilepsy. Among the 70 with Pediatric Stroke Outcome Measure scored, the median was 0.5 (IQR = 0-1.5) for children without epilepsy ( n = 63), and 6 (IQR = 0.5-10) for children with epilepsy ( n = 7). In univariable analyses, poorer 1-year outcome was associated with middle cerebral artery stroke, cortical infarcts, hemorrhagic transformation, hospital disposition not to home, and epilepsy. In multivariable analysis, middle cerebral artery stroke (odds ratio (OR) = 4.9, 95% confidence intervals (CI) = 1.1-21.3) and epilepsy (OR = 24.1, CI = 1.5-380) remained associated with poorer outcome. Conclusions Children who developed epilepsy during the first year post-stroke had poorer neurologic outcomes than those without epilepsy.