In October 2011, the Pacific Institute for Research and Evaluation (PIRE), in partnership with Big Brothers Big Sisters of Kentuckiana (BBBS-KY), was funded under OJJDP Award 2011-JU-FX0013 to assess whether a structured intervention consisting of additional post-match training and enhanced support for mentors could improve match length, youth and mentor ratings of match strength, and youth behavior and attitudinal outcomes. The project utilized an experimental research design in which volunteer mentors were randomly assigned to receive either the standard training and support offered by BBBS-KY or to receive additional training and enhanced match support in addition to the standard training. Evaluation data were collected from youth and mentors in the BBBS-KY program at match and 12 months after match. Over the course of our project, 56% of the intervention participants attended at least one additional post-match training session, suggesting that engagement in post-match training and support is a significant programmatic challenge. We found that participation in post-match training and support had a significant effect on match length and that it reduced the likelihood of closure. However, we did not find consistent effects of post-match training and support on strength of relationship ratings or on youth outcomes.