The research program ”Inspections and enforcement as instruments for enhancing environmental behavior” has focused on evaluating the effectiveness of inspections and enforcement. The results presented in this report build on the previous research program ”Efficient environmental inspections and enforcement” (Swedish EPA, Report 6558). In total, six studies have been carried out. In three studies, the communicative method ”Motivational Interviewing” has been tested in specific inspection contexts with the purpose of studying and improving the interaction between inspector and the inspectee. In addition, a theoretical, an empirical and an experimental study on the effectiveness of inspection and enforcement activities have been conducted. The aim has been to provide a wide range of analytical approaches and practical applications that can be used for both guidance and development of operational inspections and enforcement methods.