The 'Africanization' of science after decolonization was replete with dreams. Claims to Africa's place in the high-modern world, expectations of national technological and economic progress, and individual dreams of scientific discovery, professional development and fulfilled careers drove scientific work and lives. The term Africanization, coined by the colonizers, reproduced colonial notions of race but also stimulated the imagination of mid-twentieth-century African scientists, who hotly debated and enthusiastically embraced it. Half a century later, some dreams have failed, but many more remain unfulfilled. This article examines two reunions of Tanzanian and European science workers-in Amani in 2015 and in Cambridge in 2013-who had worked together in the decades after Tanzania's independence at Amani Hill Research Station, then one of Africa's foremost laboratories for research on malaria and other tropical diseases. It explores ideas of good science and experiences of social differentiation, divergent dreams and persistent tensions-and the role of joking in remembering these.