African Americans are disproportionately afflicted with end-stage kidney failure (ESRD). Whereas they constitute approximately 12 percent of the US population, they comprise 32 percent of the prevalent ESRD population. Diabetes mellitus is the predominant cause of ESRD in the U.S. population. However, hypertension is the most frequently reported cause of ESRD in African Americans. In 1990, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health launched an initiative to investigate the underlying cause, and to study mechanisms that could slow progression of hypertensive kidney disease in African Americans. An important component of this initiative is the clinical trial African American Study of Kidney Disease and Hypertension (AASK). This report provides an update on the Institute's initiative on hypertensive kidney disease in African Americans and, specifically, on the clinical trial.