Four children with a cerebrovascular occlusive accident and protein C deficiency are described. Two patients presented with an acute hemiplegia, the others suffered from a transient ischemic attack and a progressive hydrocephalus as the result of sinus thrombosis. In all cases protein C deficiency, Type 1, was diagnosed. Other causes of cerebrovascular disease were excluded. Although venous thrombosis has been extensively reported in protein C deficiency, these cases indicate that protein C deficiency is also related to arterial thrombosis. In evaluating children with cerebrovascular accidents, protein C deficiency should also be considered.