There continues to be a gap in prevention outcomes achieved in research trials versus those achieved in "real-world" practice. This article reports interim findings from a randomized controlled trial evaluating Assets-Getting To Outcomes (AGTO), a two-year intervention designed to build prevention practitioners' capacity to implement positive youth development-oriented practices in 12 community coalitions in Maine. A survey of coalition members was used to assess change on individual practitioners' prevention capacity between baseline and one year later. Structured interviews with 32 program directors (16 in the intervention group and 16 in the control group) were used to assess changes in programs' prevention practices during the same time period. Change in prevention capacity over time did not differ significantly between the intervention and control groups. However, in secondary analyses of only those assigned to the AGTO intervention, users showed greater improvement in their self-efficacy to conduct Assets-based programming and increases in the frequency with which they engaged in AGTO behaviors, whereas among non-users, self-efficacy to conduct Assets-based programming declined. Interview ratings showed improvement in several key areas of performance among intervention programs. Improvement was associated with the number of technical assistance hours received. These results suggest that, after one year, AGTO is beginning to improve the capacity of community practitioners who make use of it.