Leukotriene E(4) (LTE(4)) levels are associated with rate of pain episodes in children with sickle cell disease (SCD). Because complications of SCD manifest differently in adults than children, we examined a cohort of adults with SCD to determine the relationship between baseline LTE(4) and SCD-related morbidity. Baseline LTE(4) levels were associated with increased rates of pain and acute chest syndrome (ACS) episodes, when those with LTE(4) values in the highest tertile were compared with those in the lowest tertile (pain: risk ratio 7.1, 95% CI 1.8-27.5, P = 0.005; ACS: risk ratio 12.2, 95% CI 2.1-69.8, P = 0.005).