In order to deal with the serious problems of drug use, delinquency, and mental health problems in this country, policy makers, communities, practitioners, and advocates need to identify prevention programs that have empirical support and at the same time meet their own community needs regarding acceptability, cost, and training, and supervision. An "evidence-based" approach to prevention, one that identifies the scientific knowledge about what prevention programs work, for whom, and under what circumstances, should play a critical part in this process. The premise of this evidence-based approach is that the wide adoption of prevention programs that have been found to be successful in rigorous evaluations, will lead to successful population-based prevention strategies. A web-based registry, or database that describes the available scientific information on individual preventive trials, would be of high potential use to policy makers engaged in prevention planning for their communities. This presentation describes a model registry based on descriptions of 167 preventive trials aimed at children aged 0-6. Empirical findings are presented regarding two critical components of the registry, the measurement of the quality of the trial and the strength of evidence for a beneficial effect produced by each intervention. Implications for the use of such a registry are also discussed.