This thesis is about the history of nonhuman animal experimentation and its alternatives in the Netherlands, and specifically at the Dutch National Institute of Public Health and Environment (RIVM), in the period 1950-2020. It is characterized by a ‘multispecies approach’, in which I attempt to conduct non-anthropocentric historical research. Nonhuman animals are viewed as individuals with their own histories, which matter regardless of their importance for human histories. This means that the focus of this thesis is on the experiences of nonhuman animals used in experiments and on how these changed over time. A case study approach is taken to allow for a zooming in on the interactions between animals (including humans) on the micro level of the laboratory. The following cases are studied: the RIVM Polio-monkeys, the RIVM Animal Experiments Committee, the XPA-mice and carcinogenicity testing. In addition, the thesis contains a chapter outlining the theoretical framework, including an elaboration on the ‘multispecies approach’ taken as well as a chapter sketching macro level developments in nonhuman animal experimentation in relation to developments in regulations, science and Dutch society. Together, the chapters provide insights into recent Dutch nonhuman animal experimentation and alternatives history, on both the micro and the macro level, a subject that has been under researched. They lead to three overarching conclusions. First of all, they show that while there were several major developments in nonhuman animal experimentation practices in the Netherlands between 1950 and 2020, there were also important continuities. As we see in every case study, society, law, politics and science, remained anthropocentric practices throughout the period studied. Consequently, the possibilities for manifestation of agency by tested animals were severely limited on the micro level and completely foreclosed on the macro level. Secondly, this thesis shows that it is impossible to generalize about the effects of macro level ...