This report summarizes findings from the fourth School Nutrition Dietary Assessment Study (SNDA-IV), which collected data from nationally representative samples of school districts and schools in school year (SY) 2009-10. As in prior studies, the nutrient content of the average meals offered and served in the Nation’s schools was compared with regulatory standards in effect at the time—the School Meal Initiative (SMI) nutrition standards—as well as selected recommendations included in the Dietary Guidelines for Americans. In January 2012, USDA issued new standards for school meals to be phased in over 3 years beginning in SY 2012-13. The data reported here thus serve as a marker of progress in achieving the SMI standards, and a baseline for measuring future improvements under the new standards. The study also collected information about the availability of competitive foods—foods sold in competition to USDA school meals through a la carte sales in cafeterias, vending machines, school stores, and other venues. Finally, the study collected data from a sample of elementary schools participating in the HealthierUS School Challenge (HUSSC) and compared them to elementary schools nationwide.