This paper describes the Young Adult and Adolescent Decision Making About Contraception program, an ongoing clinical research project designed to address the problem of unplanned adolescent pregnancy from a biopsychosocial perspective. The program is described as a peer-led intervention to promote the use of contraception by teenage girls at high risk for unintended pregnancy, designed on the basis of findings from a survey of girls (N=120) in the target population. A summary is included of survey findings which provides an assessment of important demographic, intrapsychic, and interpersonal factors differentiating successful contraceptors from unsuccessful contraceptors. The population is described, the intervention techniques are outlined, and perceptions of the strengths and weaknesses of the peer intervention are discussed. The content and peer group discussion format of the 12-week program are described along with the training and performance of peer leaders. General conclusions are drawn from the peer intervention experience and the success of the program is reviewed. (NRB)