This paper explores the persistence of research organizations in their efforts to participate in the development of an emerging field of science and technology. Persistence is operationalized as the ongoing contribution of a research organization to knowledge creation and diffusion. In particular, we relate the position of a research organization in a network of R & D collaborations to its ongoing contribution to knowledge development, using data on 991 research organizations in the field of hepatitis C over the period 1979-1992/3. Event-history modeling is used to explore the influence of sociometric time-varying covariates on organizational contribution-spans. The analytical results support the hypothesis that network embeddedness is a significant determinant of organizational persistence in an emerging field. More specifically, the position of a research organization in a network of collaborative R & D activities (rather than the number of network partners or collaborative relationships) has a significant and positive influence on its ongoing contribution to the field.