Funded through the New York City Young Men's Initiative (YMI), the Cornerstone Mentoring Program is designed to support youth in key life and educational transitions as they progress into middle and high school, through the development of relationships with positive and caring adults. Launched in 2012, the mentoring program is implemented in Cornerstone Community Centers, which are funded and operated by the New York City Department of Youth and Community Development (DYCD) and operated by nonprofit provider organizations in New York City Housing Authority (NYCHA) facilities throughout the city. Cornerstone Centers offer a variety of services to both youth and adults, including afterschool programming, recreational activities, and skill-building opportunities. The YMI Cornerstone Mentoring Program complements these center-based opportunities by immersing a small number of youth in a more intensive and focused group mentoring experience. Prior to the 2015-16 program year, the YMI Cornerstone Mentoring Program served youth in grades 5-9. The program expanded to include youth in grades 10-12 during the 2015-16 program year. DYCD, which manages the YMI Mentoring Program, has contracted with Policy Studies Associates (PSA) to evaluate the YMI Cornerstone Mentoring Program since 2014. In 2014 and 2015 the evaluation primarily focused on the conditions and strategies that promote positive youth outcomes. DYCD and the Mayor's Office for Economic Opportunity, which oversees the implementation, performance monitoring, and evaluation of the majority of YMI programs, recognize that mentors are the driving force of the program and of the program's capacity to ultimately influence the intended youth outcomes. As such, in spring 2016, a PSA evaluation team examined the experiences of YMI Cornerstone mentors, through surveys of mentors (67 percent response rate) and through interviews with 15 mentors and 5 mentor coordinators, to explore how best to support mentors in working with mentees. Appendix A provides a more detailed methodology. Based on evaluation findings about mentors' experience, the goal of this report is to provide recommendations for improving the overall YMI Cornerstone Mentoring Program model by strengthening the mentor experience, based on evaluation findings about mentors' experiences. The first section of the report summarizes mentor characteristics, recruitment, and retention strategies. The second section provides details on how the mentors experience the various aspects of the YMI Cornerstone Mentoring Program model, and the third section discusses the training and support received by mentors. The fourth section discusses mentors' perceived impact on mentees development and success. Recommendations for Cornerstone leaders and mentor coordinators on how to better support their mentors are interspersed throughout these sections. Finally, the report concludes with a summary of key findings and recommendations for how DYCD can help programs to better support mentors.