Cooperative arrangements, such as partnering, have received increased interest in recent years. Several studies show however that cooperative relationships are not easily achieved in construction. Implementation of cooperative relationships requires changes in several elements of the traditional procurement procedures. The purpose of this paper is therefore to propose and test a sequential model regarding clients' cooperative procurement procedures. We especially ask: what elements in clients' procurement procedures facilitate the establishment of cooperation and trust in their relationships with contractors? The model was tested through structural equation modelling. The empirical data required for the test were collected through a survey responded to by 87 Swedish professional construction clients. The empirical results show that cooperative procurement procedures are triggered by clients' wish to involve contractors early in specification, which has a simultaneous effect on procedures regarding bid invitation and compensation. Furthermore, these simultaneous effects breed a certain kind of partner selection based on task-related attributes, which also has a direct positive effect on trust and above all on cooperation in client-contractor relationships. Besides these implications from the model, the improvement of measurements for future modelling is discussed.