Until recently, teen pregnancy and birth rates had declined in the United States. Despite these declines, U.S. teen birth and sexually transmitted infection (STI) rates remain among the highest in the industrialized world. Given the need to focus limited prevention resources on effective programs, Advocates for Youth undertook exhaustive reviews of existing research to compile a list of those programs proven effective by rigorous evaluation. Nineteen programs appeared in "Science and Success" when it was first published in 2003; seven additional programs are included in "Science and Success, Second Edition." Advocates for Youth established a set of stringent criteria for determining program effectiveness. Staff then conducted an exhaustive literature review. This executive summary provides a brief description of the 26 programs that meet the rigorous criteria. [For the full report, "Science and Success: Sex Education and Other Programs That Work to Prevent Teen Pregnancy, HIV, and Sexually Transmitted Infections. Second Edition," see ED582011.]