Two pediatric patients with acute leukemia who developed optic nerve head leukemic infiltration are presented. In one patient both eyes were involved at diagnosis as well as her central nervous system. Despite systemic and intrathecal chemotherapy she lost her vision within a few weeks. Cranial irradiation at that point could not reverse this outcome. In the second patient optic nerve head infiltration was found a few months after diagnosis, treated promptly with cranial irradiation and her vision was saved. Her central nervous system (CNS) was not involved at any time. It is stressed that ocular complaints including eye pain or blurred vision in the pediatric patient with leukemia should be investigated without delay by an ophthalmologist. In the young child these complaints may be absent and change in the visual behavior should then alert the pediatric oncologist for possible ocular problems. If optic nerve head leukemic infiltration is diagnosed and promptly treated with emergency radiation, vision can be salvaged.