Each year, about 5% of people admitted to U.S. hospitals (about 2 million people) acquire an infection there. These infections cause nearly 20,000 deaths each year, and cost an estimated $4.5 billion to treat. Handwashing is the single most effective measure for preventing hospital-acquired infections. Despite widespread knowledge of the importance of handwashing, health care workers wash their hands far less often than is indicated. This Issue Brief describes a novel strategy to improve handwashing among hospital personnel, by involving the people with the most to gain—the patients themselves.