This paper investigates the impact of individuals’ social ties at organizational entry on the formation of intraorganizational networks. When individuals enter organizations with one or more preentry relationships in place, I argue they form more extensive networks post entry than their untied counterparts. However, it is also suggested that under some conditions—i.e., when quality is more certain—the relationship between pre- and postentry social structure is contingent on individuals’ quality attributes. I test and find support for these hypotheses in a study of new business and law professionals. The results indicate that individuals with an initial advantage in social ties form more extensive networks post entry than those without such an advantage, and that when certainty about quality is high, this effect depends on the quality attributes of the new entrants. Implications of this study for research on social networks, resource accumulation, and inequality are discussed.