This article reviews changes in the accountability landscape that have occurred for foundations in recent years and several precedents for foundation performance assessment. The authors then present a model of portfolio assessment that is used for organizational accountability and learning. This model, which was piloted in 2002 and 2003 for the Minnesota Partnership for Action Against Tobacco (MPAAT) and is in continuing use today, consists of a report card system based on an organizational logic model and the intended intermediary outcomes of MPAAT's funding. The model is conducted by an external oversight evaluator and results in aggregated performance measures and findings that are publicly disseminated on an annual basis. This approach to portfolio assessment may be especially relevant for smaller foundations, public trusts, community foundations, health care conversions, government agencies, and other organizations that disburse grants in politically charged fields, such as reproductive rights, the environment, and health policy.