This epidemiological study examined the 5-year changes in intra-abdominal adiposity assessed by computed tomography in a minority cohort of the Insulin Resistance Atherosclerosis Study. The cohort included male and female African Americans (n=389) and Hispanic Americans (n=844). During five years, increases in levels of both intra-abdominal and subcutaneous adipose tissue were observed in young adults; such increase being attenuated in older adults. The age “effect” was even more pronounced in African Americans than in Hispanics, particularly among women. Absolute increases in cross-sectional areas of intra-abdominal adipose tissue were 18 cm2 and 12 cm2 in African American and Hispanic women compared to 13 cm2 and 7 cm2 in African American and Hispanic men. Despite these ethnic differences, young adulthood was found to be a critical period for accumulation of intra-abdominal fat suggesting a sensitive period for the modulation of the related type 2 diabetes and cardiovascular disease risk.