This paper sketches the rise and transformation of workplace medical examinations in the early twentieth century United States. The paper suggests that legislative changes as well as the independent actions of physicians helped create the conditions within which businesses made use of medical examinations, and that further legislative changes remade the purposes to which medical examinations were put. In the beginning of the twentieth century, the expansion of workplace medical examinations occurred in such a way that made use of medical technique to produce knowledge about populations and aggregates, in order to guide business practice and to provide some measure of medical improvement in employees' lives. After workmen's compensation laws, however, this corporate capacity for medical knowledge production became repurposed, becoming increasingly put to work to control employers' financial costs under workmen's compensation by screening out workers judged likely to suffer particularly expensive injuries. Ultimately, medical examinations in industry came to be used to care for the financial body of corporate employers, at least as much as the individual bodies of working people.