Increasingly, companies are using alliances and joint ventures to pursue entrepreneurial opportunities. These collaborations are voluntary arrangements between two or more firms that exchange, share, bundle, and create resources in pursuit of entrepreneurial opportunities. This paper proposes that the innovativeness and risk characteristics of these entrepreneurial collaborations significantly influence the outcomes that partner firms realize. Furthermore, interfirm trust works to moderate the effects of these characteristics and allows partners to effectively manage these arrangements. Using data from a sample of alliances and joint ventures engaged in new product development in the telecommunications, medical, and electronics industries, we empirically test the effects of these characteristics on partner satisfaction and partnership success.