Perinatal stroke in twins without co-twin demise has not been well-described. In this study, the International Classification of Diseases- 9th edition code searches and medical record review were used to identify all children with arterial ischemic stroke examined in a pediatric stroke clinic over a 2-year period. Four of the 35 children (11.4%) with perinatal arterial ischemic stroke were twins; none had co-twin demise. No co-twin had any clinical evidence of perinatal stroke. The most common findings on prothrombotic evaluation were elevated antiphospholipid antibodies (2), elevated lipoprotein a (2), and elevated Factor VIIIc (2). Twin gestation without co-twin demise may be a risk factor for perinatal stroke, and might help explain the higher incidence of cerebral palsy in twins.