It is well known that black Americans have a higher risk for low birth weight (LBW) than white Americans. In addition, blacks are at a higher risk for hypertension (HT), non-insulin dependent diabetes mellitus (NIDDM), and end-stage renal disease (ESRD), particularly ESRD attributed to HT (ESRD-HT) and NIDDM (ESRD-NIDDM). It has been shown that LBW is associated with postpartum anatomic and functional alterations in the kidney and pancreas as well as with progressive renal damage in animals and increased risk for HT and NIDDM during adulthood in humans. Based on these empirical findings, it is here proposed that a greater risk of HT, NIDDM, and ESRD, particularly ESRD-HT and ESRD-NIDDM, in black Americans during adulthood may be partly related to their higher risk of LBW. However, LBW is proposed here as a component factor rather than a sufficient cause or a necessary factor for the development of these diseases. The ultimate contribution of LBW to the black/white disparities regarding HT, NIDDM, and ESRD may depend not only on the black/white differences in LBW but also on the race-specific prevalences of other component factors, both environmental/behavioral and genetic, that may or may not require the presence of LBW to cause each of these diseases.