Organizational advocacy capacity is an increasingly important area of inquiry, raising questions about the opportunities (and limits) for achieving and sustaining policy change. The California Endowment implemented the Clinic Consortia Policy and Advocacy Program to expand grantee advocacy capacity to support the policy and operational needs of California's community clinics. In-person meetings with decision-makers and developing working relationships were among the key advocacy activities undertaken by 19 grantees. Grantees secured several policy wins through a variety of strategies, including mobilizing member clinics to be potent advocates. The "return on investment analysis" indicates that grantees secured policymaker support for clinic programs and services that brought member clinics a total of $1.63 billion from 2001 to 2009 to increase access to care. Longer-term outcomes achieved by grantee policy and program initiatives included a strengthened health care safety net and increased access to health care for medically underserved Californians. Funders of advocacy and policy change initiatives are encouraged to consider the resources needed to build and sustain advocacy capacity, including grantee technical expertise, partnerships with stakeholders, and time required to expand advocacy capacity.