We propose a series of dissemination conferences aimed at prevention researchers. The topic of these dissemination conferences will be methodology for longitudinal research. The conferences, called Summer Institutes on Longitudinal Methods, will be held annually from 1999 through 2003. The long-term objective of these conferences is to ensure that the field of prevention research maintains highest, state-of-the-art methodological standards. The proposed conferences will contribute to this in two ways. First, they will help prevention researchers gain conceptual and practical understanding of state-of-the-art methodological and statistical procedures so that they can use these procedures in their research. Some of the cutting-edge methodological research to be disseminated at these conferences will originate from the NIDA-funded Center for the Study of Prevention through Innovative Methodology. Second, the conferences will foster networking among prevention researchers who are interested in methodology and statistics, for the purpose of sustained mutual support and sharing of information. The conferences are to be held at the Penn State Conference Center, a new facility opened in 1994. We have held similar dissemination conferences in 1996 and 1997 with considerable success, and will hold another in May 1998.