constitutes a strong trend of this field of research.Allen, Eby, Poteet and Lima (2004) identified two major types of studies that examined the benefits of mentoring for proteges and considered both for their metaanalysis. The first one included studies that compared the outcomes across mentored and non-mentored individuals. The second type of studies consists on attempts to correlate mentoring functions (career and psychosocial mentoring) and proteges outcomes.In an attempt to summarize literature on formal mentoring, Allen, Eby and Lentz (2006b) showed that most studies tend to a) compare formal and informal mentorships, b) examine mentor functions and protege outcomes and c) compare those with formal mentors and those without mentors. Underhill (2006) points the lack of research comparing mentored and nonmentored groups of individuals. Such comparison, she argues, is fundamental to assess the effectiveness of mentorships. Although scholars recognize the importance of evaluating the benefits of mentoring, research on that issue appears to be relatively disperse and unconclusive.Researchers have considered a wide variety of benefits associated with mentoring. Several criterion variables to evaluate mentorship effectiveness have been used. Allen et al (2004) divided them into objective and subjective outcomes. Within the first group are such variables as number of promotions and income (Wallace, 2001; Chao, 1997) or protege performance (Tonidandel, Avery & Phillips, 2007). Subjective outcomes are those such as career clarity for proteges (Wanberg, Kammeyer-Mueller & Marchese, 2006) mentoring functions, role modelling and mentorship perceived quality (Allen, Eby & Lentz, 2006), perceived program effectiveness (Allen, Eby & Lentz, 2006b), organizational socialization (Chao, 1997) and so forth.It is also important to note that most of current and past research has been centred on protege-related outcomes, although some have considered the potential benefits of such a relationship for mentors as well (e.g. Wanberg, Kammeyer-Mueller & Marchese, 2006).The list of factors influencing the success of mentoring relationships seems even longer. For instance, Allen, Eby and Lentz (2006b) considered mentor commitment and program understanding as mediators on the relationship between program design features (e.g. training, match input, voluntary participation, etc.) and program outcomes, namely, perceived program effectiveness for both mentors and proteges. They found that training quality had both direct and indirect effects on the outcomes measured for both parties of the mentoring dyad. Moreover, they also found match input the extent to which proteges and mentors participate on the matching process to influence perceived effectiveness of the program through mentor commitment and program understanding.Tonidandel et al (2007) found support for the influence of amount of mentoring and length of relationship on proteges subsequent performance, though such effects were moderated by mentor success. In other words, being under orientation of a successful mentor for a long time fostered positive outcomes for mentees. On the other hand, a long relationship with an unsuccessful mentor had a detrimental effect on proteges performance.Wanberg, Kammeyer-Mueller and Marchese (2006) focused on personality aspects (proactivity and openness to experience) of both mentors and proteges and their influence on mentoring outcomes. They found support for the association of mentors proactivity and proteges perceived similarity to ones mentor with the amount of mentoring