This article summarizes and critically evaluates the scientific literature for the annual and lifetime medical care costs of obesity in women in the United States. Studies involving actual and projected costs are reviewed. Studies were favored that included large, nationally representative samples; accounted for the influence of potential confounding factors; and adjusted for decreased survival in obese women when comparing costs with women of normal weight. Despite a wide variety of methodology in model cost estimation and projection in the studies published, the evidence suggests significant costs attributable to overweight and obesity in women that vary throughout the lifespan and by specific racial and obesity categories.