In this study, we seek to advance the network perspective on new venture internationalization by examining the role of networks in accelerating new venture sales into foreign markets. We propose that knowledge derived from ventures' technology and marketing alliances increases the likelihood that new ventures begin exploiting opportunities in international markets. We also argue that the extent to which the networks open the venture to new knowledge or constrain it to knowledge already shared among the partners will influence the initiation of foreign sales by a venture. Using a longitudinal dataset of 118 ventures in the U.S. biotechnology industry, we confirm that different types of alliances (and, therefore, different types of knowledge—technology and marketing knowledge) differentially impact the likelihood of new venture internationalization. Moreover, network cohesion among venture alliances increases the likelihood that marketing alliances will promote initial foreign market sales, but decreases the likelihood that technology alliances will do so. Our research is a timely response to a call for the study of interactive effects among network structure, complex tasks, and time, and it provides a possible explanation for certain unexpected findings in studies that did not consider the effects of time. Copyright © 2010 John Wiley & Sons, Ltd.