The Atlanta Sickle Cell Consortium represents more than 2600 pediatric and adult patients with sickle cell disease (SCD) in the metropolitan Atlanta, Georgia, area receiving care at four major locations, each providing comprehensive care 24 hours a day, 7 days a week. Both transfusion services that support these sites use two levels of prospective phenotype matching to decrease the rates of alloimmunization. Although exact rates are unknown and are currently under investigation, alloimmunization occurs infrequently with the exception of chronically transfused SCD patients, who represent the minority of active SCD patients. With increasing availability, red blood cell genotyping will be used in the near future both for determination of predicted patient phenotypes and for provision of genotypically matched donor units.