To quantify annual costs attributable to obesity, including both increased medical expenditures and absenteeism, separately for overweight and three categories of obesity (i.e., obesity grades I, II, and III) among men and women with full-time employment. Standard econometric methods were used to separately estimate overweight and obesity-attributable medical expenditures and absenteeism. The civilian noninstitutionalized population of the United States. Two nationally representative and publicly available datasets (with response rates of at least 60%) were restricted to participants 18 to 64 years old and employed full-time for the entire year. The final datasets used to estimate obesity-attributable medical expenditures and absenteeism included 20,329 and 25,427 adults, respectively. MEASURES. Annual medical expenditures and missed work days due to illness or injury. ANALYSIS RESULTS: Overweight and obesity-attributable costs range from dollar 175 per year for overweight male employees to dollar 2485 per year for grade-II obese female employees. The costs of obesity (excluding overweight) at a firm with 1000 employees are estimated to be dollar 285,000 per year Obesity results in significant increases in medical expenditures and absenteeism among full-time employees. Approximately 30% of the total costs result from increased absenteeism, and although those with grade-III obesity represent only 3% of the employed population, they account for 21% of the costs due to obesity. These estimates do not consider other potential costs associated with obesity, including disability and presenteeism.