As a new delivery mode, integrated project delivery (IPD) relies on highly trust-based collaboration among project parties. Thus, selecting the appropriate parties is important for successful IPD. Although traditional selection methods, which are primarily based on only the lowest tender price or multiple criteria other than price, can help select parties that can complete an integrated project, they are not completely suitable for IPD when trust and collaborative relationship among the project parties are considered. To improve upon this shortcoming of established methods, a new method based on the concept of an interorganizational transactive memory system (I-TMS) is established in this paper. The I-TMS drives group members to be mutually trusting and cooperatively integrate their professional knowledge, which reflects the idea of collaboration that underlies IPD. In this study, party selection for IPD was achieved via two processes. First, this study developed an I-TMS rating scale and conducted a questionnaire-based analysis to verify its reliability and validity quantitatively. Second, this study selected an appropriate combination from seven combinations of party candidates. In addition, this study analyzed the appropriate combination using social network analysis (SNA). The results suggest that project parties with a low I-TMS degree should engage in frequent interaction to foster mutual cognition and trust and improve team collaboration for IPD. (C) 2015 American Society of Civil Engineers.