Evaluation plays a key role in developing and sustaining community partnerships and coalitions. We recommend focusing on three levels of coalition evaluation that measure (a) processes that sustain and renew coalition infrastructure and function; (b) programs intended to meet target activities, or those that work directly toward the partnership's goals; and (c) changes in health status or the community. A tendency to focus on quick wins and short-term effects of programs may explain why some coalitions are not able to achieve systems and/or health outcomes change. Although measuring community-level or system changes (e.g., improving environmental quality or changing insurance coverage policies) is much more difficult than evaluating program outcomes, it is essential. This article presents challenges that coalition practitioners and evaluators face and concludes with practical resources for evaluation.