Nearly twice as many American Indian (Al) women have their first child during their teenage years (46%) than any other racial or ethnic group in the United States (25%). Reservation life compounds challenges for Al teen mothers, and places them and their children at significant lifetime risk for drug abuse and other health and behavior problems. Two decades of research support the efficacy of prenatal and early childhood nurse delivered, home visiting programs to prevent health and behavior problems for low income, teen mothers and their children. Given the risks factors confronting young Al families and the shortage of indigenous nurses on reservations, a randomized controlled trial is proposed to assess the efficacy of a culturally-adapted, paraprofessional delivered, home visiting program for reservation-based Al teen mothers and their children. The nationally proven intervention model was selected, adapted, and piloted within the study communities since 1998. Eligible expectant Al teens (N=320), ages 12-19 and up to 28 weeks gestation from four reservation communities-will be randomized (1:1) to the Family Spirit Intervention (FS) + Optimized Standard Care vs. Optimized Standard Care (OSC) alone. The FS intervention is a 52-session home visiting program, delivered by Al paraprofessionals, beginning in pregnancy and continuing until the child is 24 months old (approximately 27 months). OSC participants receive free transportation to standard prenatal and well baby visits and written health promotion materials relevant to teen mothers. Masked independent evaluators will assess parental competence, and mother and child health and behavior outcomes at multiple intervals until the child is 36 months old. The study methods have been piloted in preliminary studies funded by SAMHSA. The Johns Hopkins Center for American Indian Health, the applicant institution and coordinating center, has a 22-year history of working with the participating Al communities. Consultants to this application are expert in parenting, home visiting interventions and early childhood assessment.