In this article we examine labour politics and unionization at a scientific research station: the former Institute of Malaria and Vector Borne Diseases ('Amani') in north-eastern Tanzania. Drawing on an analysis of an archive found at Amani, this paper approaches the process of decolonizing and Africanizing science and medical research from the perspective of African technicians. The technician cadre at Amani was drawn to scientific employment as it seemed to offer the promise of training, education and advancement. The union at Amani argued that African labour was crucial to the production of scientific knowledge at the station and that there ought to be a 'ladder' of promotion and progress that led from auxiliary scientific technician to independent researcher. The daily politics of the decolonization of science was conducted as everyday contentious labour relations and as increasingly vociferous claims upon the cultural power of science by African workers. Drawing attention to the social and spatial practices of African workers at Amani in the 1960s, we argue that Amani functioned not just within globalized networks of tropical medicine and scientific research but as a place bound both to local economies of labour and to larger geographies of African ambition and aspiration.