Health care–associated infections (HAIs) are a known contributor to preventable patient harm. This AHRQ publication offers 19 papers that explore government-funded research into HAIs, including lessons learned from the design and implementation of prevention efforts along with projects that sought to detect and measure HAI incidents to determine risks. The report discusses specific infections, including clostridium difficile and methicillin-resistant staphylococcus aureus, as well as common conditions, such as central line-associated blood stream infections and catheter-associated urinary tract infections. A recent AHRQ WebM&M perspective reviews how infection prevention fits into a safety program.