Although the increasing public health impact of excess body weight in the U.S. general population has received national attention, the impact of excess body weight among active duty military personnel is unknown. A study was conducted to determine the direct (increased medical care) and indirect (lost workdays) costs of excess body weight among active duty Air Force (ADAF) personnel in 1997. Based on measured height and weight values, in 1997, 20.4% of ADAF men and 20.5% of ADAF women had body weights that exceeded their official maximum allowable weight for height. Total excess body weight-attributable costs were estimated at $22.8 million per year, with annual direct and indirect costs estimated at $19.3 million (approximately 6% of total annual expenditures for ADAF medical care) and $3.5 million, respectively. Attributable lost workdays were estimated at 28,351 per year. Annual excess body weight-attributable costs among ADAF personnel are high, both in dollars and lost duty days.