This article investigates the construction of laboratory animal science as a version of ''good science.'' In the 1950s, a transnational community of scientists initiated large-scale standardization of animals for biomedicine, which included the standardization of care of laboratory animals as well as the development of guidelines and regulations on laboratory animal use. The article traces these developments and investigates how the standardization work took part in enacting laboratory animals as compound objects of care-and laboratory animal science as being an intrinsically ethical practice-as good science. Importantly, the analysis shows how technological development is inextricably accompanied by ethics, as it is the result of complex social organization involving multiple ethical commitments. By investigating the development of laboratory animal science historically, it is possible to tease out how values, norms, and standards have been made integral to specific practices in the first place and how they have developed and been sustained over time. The article contributes to current concerns in science and technology studies about how life is made, valued, and ordered at the intersection of science and society and in biomedicine,