Laboratory ethnographies have provided valuable insights in the workings of contemporary science and technology and about facts in the making. Nearly all these ethnographic studies have been conducted at nonprofit research institutes. In this article, the authors argue that it is time for science and technology studies (STS) ethnography to direct its gaze toward for-profit knowledge production sites. The authors do so, based on a long-standing recognition that nonprofit academic laboratories do not have a monopoly on knowledge construction. First, they (...) historicize STS’ focus on public knowledge production, distinguishing between two roles for STS. Second, they argue that relationships between industry and society have changed, resulting in increasing corporate transparency. Third, they argue that this change enables STS ethnography to enter corporations and corporate laboratories. The authors conclude by proposing a research agenda for the social study of corporate science. (shrink)