Sexually active adolescents are at risk for unintended pregnancy. Teen pregnancies can be prevented by consistent use of birth control, such as oral contraceptives. However, many teens forget their daily doses and eventually stop using oral contraceptives altogether. Teen pregnancies are more likely to be medically complicated and can adversely impact the teen, her child, and their community. Cell-phone use is becoming widespread, and teen cell-phone users frequently use text messaging. We describe a study in which we use cell-phone text-messaging technology in a novel way: we provide daily oral contraceptive dosing reminders and educational messages and evaluate oral contraceptive continuation at 6 months. We will use the information we obtain to develop specific, practice-based interventions to improve reproductive health programs and policies.