We designed a decision analysis model comparing 4 treatment strategies for severe sickle cell disease: no intervention, hydroxyurea (HU), chronic transfusion, or stem cell transplant (SCT). The treatment strategy associated with the highest average utility (quality of life) was SCT (0.85). Average utilities for no treatment, chronic transfusion, and HU were 0.68, 0.71, and 0.80, respectively. Our model was quite sensitive to quality-of-life estimates, indicating that a true comparison of HU and transplantation cannot occur until investigators directly measure the health-related quality of life in children with sickle cell disease during HU therapy and after SCT.