The risk of end-stage renal disease (ESRD) is higher in people of African ancestry than in those of European ancestry, but whether sickle cell trait (SCT), which is relatively common in black individuals, is a risk factor for ESRD is unclear. Naik et al. analysed the presence of SCT and the incidence of chronic kidney disease and ESRD in >9,900 black individuals from the Reasons for Geographic and Racial Differences in Stroke cohort study. SCT was strongly associated with risk of progression to ESRD. The researchers suggest that this association might have public policy implications for the counselling and treatment of SCT carriers.