Traditionally, research into antecedents, characteristics, and outcomes of supplier integration has mainly focused on integrating suppliers into new product development. What is urgently needed is a more comprehensive analysis of supplier integration activities. This research, which is based on responses from 173 industrial firms as well as supplementary interviews with purchasing executives, develops the notion of a phase-differentiated approach toward supplier integration. It further provides insights into supplier integration in the development phase and supplier integration in the industrialization phase with respect to, for example, the degree of integration, the distinct managerial approaches, and the benefits sought by the buyer and the supplier. Additionally, results of an industry-level analysis examine how various industries approach supplier integration.