Excess body weight (EBW), which continues to become more prevalent, is a clear contributor to cardiovascular disease (CVD), the leading cause of death and disability among U.S. adults. Information on the economic impact of CVD associated with EBW is lacking, however. To estimate the direct medical costs of CVD associated with EBW. We conducted a population-based analysis of direct medical costs by linking the 1995 National Health Interview Survey and the 1996 Medical Expenditure Panel Survey. The study subjects are adults (aged > or =25 years, excluding pregnant women) in the non-institutionalized, civilian population in 1996. The prevalence of CVD among people in the normal weight (body mass index [BMI] > or =18.5 to <25), overweight (BMI > or =25 to <30), and obese (BMI > or =30) groups was 20%, 28%, and 39%, respectively. There were 12.95 million CVD cases among overweight people, more than 25% of which was associated with overweight. There were 9.3 million CVD cases among obese people, of which more than 45% was associated with obesity. This extra disease burden led to $22.17 billion in direct medical costs in 1996 ($31 billion in 2001 dollars, 17% of the total direct medical cost of treating CVD). The strong positive association between EBW and CVD, and the significant economic impact of EBW-associated CVD demonstrate the need to prevent EBW among U.S. adults.