Social networks have recently emerged in the management discipline as a unique way of studying individuals and groups in organizations. While traditionally used in the analysis of un-bounded networks, applying social network analysis techniques to bounded work groups and organizational teams has become increasingly popular. Past research has established relationships between in-degree social network centrality and individual performance as well as social network density and overall group performance. This field study, conducted at a military training course, attempted to further refine this social network-performance relationship by modeling characteristics of both the formal and informal work group networks in relation to performance at the individual as well as group levels. A sample of 406 students in 28 groups showed empirical evidence that individual performance is positively related to centrality in the formal social network while a negative relationship was found between performance and centrality in the informal social network.