From its 1958 origin in defense, the Advanced Research Projects Agency (ARPA) model for research funding has, in the last two decades, spread to other parts of the US federal government with the goal of developing radically new technologies. In this paper, we propose that the key elements of the ARPA model for research funding are: organizational flexibility on an administrative level, and significant authority given to program directors to design programs, select projects and actively manage projects. We identify the ARPA model’s domain as mission- oriented research on nascent S-curves within an inefficient innovation system. Finally, we describe some of the challenges to implementing the ARPA model, and we comment on the role of ARPA in the landscape of research funding approaches.