To meet the Dutch Government goal of reducing CO 2 emission, target groups must intensify their efforts to conserve energy. Novem, 1 in commission of the Dutch Ministry of Environmental Affairs, developed a strategy to effectively change the behaviour of target groups. This paper answers the questions: what are the influencing determinants of energy-relevant behaviour of housing associations; and which policy instruments are most suitable for an intervention strategy? From a survey of housing associations we determined the factors making up the determinants of behaviour. The four main types of policy instruments-judicial, economical and communicative instruments and physical provisions-were analysed for their active ingredients. An intervention strategy was then based on matching the factors making up the target-group determinants and the active ingredients of the policy instruments. The factors: attitude, feedback of peer organizations and feedback from authorities strongly influence the energy-relevant behaviour of housing associations and the most effective policy instruments have a facilitating and encouraging character and include covenants with local authorities. We conclude that this method forms a solid basis for formulating an intervention strategy to change the behaviour of housing associations.