In the Balanced Budget Act of 1997, U.S. Congress authorized a scientific evaluation of the Title V, Section 510 Abstinence Education Program. This report presents final results from a multi-year, experimentally-based impact study conducted as part of this evaluation. It focuses on four selected Title V, Section 510 abstinence education programs: (1) My Choice, My Future! in Powhatan, Virginia; (2) ReCapturing the Vision in Miami, Florida; (3) Families United to Prevent Teen Pregnancy (FUPTP) in Milwaukee, Wisconsin; and (4) Teens in Control in Clarksdale, Mississippi. Based on follow-up data collected from youth four to six years after study enrollment, the report presents the estimated program impacts on youth behavior, including sexual abstinence, risks of pregnancy and sexually transmitted diseases (STDs), and other related outcomes.