An Israeli Arab family with type I antithrombin III (AT-III) deficiency with several affected symptomatic members in three generations is reported. The propositus presented with deep vein thrombosis and pulmonary emboli associated with gestation. The propositus infant presented at the age of 2 weeks with superior sagittal and rectus sinus thrombosis. Hereditary AT-III deficiency should be considered in infants with cerebral thrombosis, especially if they have a family history of thromboembolism. The role of prophylactic therapy by AT-III concentrates in these infants should be further assessed.