The National Diabetes Education Program, cosponsored by the National Institutes of Health and the Centers for Disease Control and Prevention, employs mass media communications, public-private partnerships, and dissemination of information and education tools to address the diabetes epidemic in the United States. The program's goal is to help reduce the morbidity and mortality from diabetes and its complications by improving the treatment and outcomes for people with diabetes, promoting early diagnosis, and preventing onset of diabetes. Evaluation is an integral component of the National Diabetes Education Program's planning and implementation process. The program's evaluation is based on the Centers for Disease Control and Prevention's Framework for Program Evaluation in Public Health, which has guided program planners and evaluators in developing measurable short-term, midterm, and long-term outcomes. We describe how the National Diabetes Education Program has applied the evaluation framework, demonstrating how multifaceted health communications programs can design program evaluations to answer key questions about program processes and outcomes.