Introduction:The neurologic changes of sickle cell anemia (SCA) are particularly devastating and include acute stroke, silent infarctions, and cerebral hypoxemia that together result in cumulative damage and significant neurocognitive deficits. Executive functioning and attention are the most commonly reported deficits with individuals with SCA scoring on average ten points lower on measures of full scale intelligence compared to matched unaffected controls, translating to poor academic achievement and later job attainment. Hydroxyurea is the standard-of-care in patients with SCA with a growing body of evidence suggesting a role in neuroprotection. However, although encouraging, until now, the only studies have involved children who began hydroxyurea in grade school, well after the onset of SCA-related neurocognitive decline. Beginning in 2014, Cincinnati Children's Hospital Medical Center (CCHMC) began treating children with SCA as young as six months with hydroxyurea; these children have had few SCA-related complications and offer a unique population to evaluate the effects of the early introduction of hydroxyurea on neurocognition.