In this study, the authors examined the distribution and odds of occupational injury among hourly employees of a US aluminum manufacturing company by body mass index (weight (kg)/height (m)(2)). In 2002, height and weight data on 7,690 workers at eight plants were extracted from medical records from annual physicals, and body mass index was categorized. Information on traumatic injuries recorded between January 1, 2002, and December 31, 2004, was obtained from a company injury surveillance system. Twenty-nine percent of the employees (n = 2,221) sustained at least one injury. Approximately 85 percent of injured workers were classified as overweight or obese. The odds of injury in the highest obesity group as compared with the ideal body mass index group were 2.21 (95% confidence interval: 1.34, 3.53), after adjustment for sex, age, education, smoking, physical demands of the job, plant process and location, time since hire, time in the job, and significant interaction terms. Injuries to the leg or knee were especially prevalent among members of this very obese group. Research findings support an association between body mass index and traumatic workplace injuries among manufacturing employees. Workplace safety personnel might consider adding policies or programs that address weight reduction and maintenance as part of ongoing comprehensive workplace safety strategies.