In the context of the Great Recession, unrestricted funding was crucial for nonprofits. It is their lifeline at a time when they are simultaneously faced with reduced resources and increased demand for services. Despite growing use of core operating support (COS) as a way to support services, evaluating the effects of this funding strategy remains a challenge. This roundtable, presented by Harder+Company Community Research and The California Wellness Foundation, is designed to engage evaluators, funders, and others in a discussion of approaches to evaluating COS. We will share findings and promising practices from the evaluation of The California Wellness Foundation‘s COS grants during the recession.#Non-ProfitsandFoundationsEvaluation