Recognizing that some early endings are unavoidable, the author maintains that many mentor-mentee relationships quickly dissolve due to factors that may be avoidable, such as disappointment and dissatisfaction with the relationship. Findings from a range of research studies are offered. Higher levels of program support may be required for matches made with older youth and those with more complex problems. Early attention to expectations mentors and youth bring to the mentoring relationship is also cited, including discussion of ending the relationship appropriately. Training directed toward helping mentors identify some of their cultural and class-based values and beliefs and developing skills for effectively engaging in cross-cultural relationships with youth could be critical to the success of some mentoring relationships. Monitoring of matches and ongoing training for mentors are among the program practices associated with more positive youth outcomes, a practice that may also serve to reduce early endings. Regular contact with matches on a periodic basis may provide program staff the opportunity to identify difficulties as they arise and step in to provide assistance or to facilitate termination if necessary. Ongoing training may provide mentors with the chance to receive assistance with challenging situations and assist them with continued development of their skills as a mentor. By identifying and addressing common pitfalls in formal mentoring relationships, programs can better support mentors and youth in their efforts to build close, enduring, and growth-promoting relationships. The article is followed by suggestions on how practitioners can incorporate the research findings into mentoring programs and a list of additional resources. [The 10-issue "Research in Action" series, edited by Jean E. Rhodes, is the initial project of the MENTOR Research and Policy Council, charged with taking current mentoring research and translating it into useful, user-friendly materials for mentoring practitioners. For full series, see ED502220 through ED502229, inclusive.