Abstract
The Trelleborg project ran between 1999 and 2002. This article describes and analyzes the processes relating to institutionalization and social change, and their consequences, within the project. The research, funded by the Swedish National Institute of Public Health, was based on qualitative data collected during the project, including focused interviews with 12 key individuals, five focus group interviews, two evaluation seminars, and a large number of meeting minutes. The article concludes that positive interaction between organization elites is a prerequisite for institutionalization. However, the elites within an organization also have to take external pressures into account when transforming an ad hoc initiation into sustained activity.