Combining mentoring theory with social network theory, this study investigates the formation of mentoring networks. In a sample of 127 military officers, we test hypotheses regarding the relationship between self-monitoring personality and mentoring network characteristics. Protege's self-monitoring orientation predicted the tie strength in his or her mentoring network Results support the statement that personality variables predict the structure of social networks. In addition, results of the social network analysis confirm that individuals receive mentoring assistance from multiple mentors and that the mentoring network characteristics a protege possesses differ depending on his/her self-monitoring orientation. Key words: Mentoring Network, Self-monitoring, Social Network, Personality Introduction Recently, the concept of social capital has gained importance as a powerful factor explaining the relative success of actors in a number of areas which are of central concern to organizational researchers (Adler/Kwon 2002). Due to increasing interest in leveraging social capital within organizations, informal and formal mentoring has attracted the attention of academics and practitioners as a potentially critical developmental tool (Wanberg/Welsh/Hezlett 2003). Academics and practitioners have recognized that mentoring relationships are valuable because of their impact upon employee socialization, learning, career development, expatriate adjustment, and the preparation of employees for managerial positions (Dockery/Saal 1998; Laabs 1998; Noe 2002). In the past twenty years, the benefits that proteges receive from traditional oneto-one mentoring relationships have been the focus of much of the research on mentoring. However, scholars have begun to pay attention to relationships of proteges with multiple mentors including senior colleagues, peers, and even subordinates (Higgins/Kram 2001). Changes in the current career environment caused by the flattening of organizational structures and the diversification of organizational membership suggest that people need to strive to a broader group of individuals in order to receive sufficient mentoring support. Yet despite the theoretical readiness to reconsider mentoring from the social network perspective (Podolny/Baron 1997; Higgins/Kram 2001; Higgins/Thomas 2001; De Janasz, Sullivan/Whiting 2003), there is not much understanding about the concept of mentoring networks so far. In a large part of existing literature on the topic, mentoring has been conceptualized as an intense interpersonal exchange between a more senior employee (i.e. the mentor) who provides advice, counselling, feedback, and support related to career and personal development, and a less experienced employee (i.e. the proteges) (Hunt/ Michael 1983; Kram 1985). In this respect, individuals beyond one single mentor seldom have been considered. Further, the emphasis on the consequences of social network rather than its origins has resulted in neglecting the importance of the antecedents of mentoring networks. Especially the social network researchers, focusing on social structure, have omitted the importance of individual personalities in network analysis. Scholars studying the structure of networks tend to ignore the attributes of actors such as personality, because outcomes are assumed to derive from embeddedness in relational systems. In recent years, however, these long-ignored interrelations of individual personalities with social networks have gained increased notice from network researchers (Burt/Jannotta/Mahoney 1998; Kilduff 1992; Mehra, Kilduff/Brass 2001; Klein/LJm/Saltz/Mayer 2004). For example, in a recent critique of social network research, Salancik (1995) called for specific network theory to explain why certain characteristics exist. The current research question linking personality and the structure of social networks has its roots in early organizational research. …