The professional consultancy services provided by construction management consultants (CMC) are important supplements to clients' management of project execution. However, CMCs' services, if not carefully managed, cannot bring salient contributions. This paper aims to empirically examine how clients' delegation to CMCs affects client-consultant capability integration in project management processes. Based on a comprehensive literature review, a conceptual capability integration model was developed. A triangulated approach was adopted to collect qualitative and quantitative data. Social network analysis (SNA) and case analysis provide exploratory evidence on the capability integration model. Partial least square based structural equation modeling (PLS-SEM) analyses tested the model hypotheses statistically. The results suggest that both clients' and CMCs' capabilities contribute to project management processes, although clients' contributions are more significant. Delegating more responsibilities to CMCs better utilizes their capabilities and at the same time does not restrict clients' contributions. Theoretically, these findings provide empirical support to the theory of temporal project organization and map the client-consultant collaboration interface. In practice, clients should better utilize CMCs' capabilities by designing appropriate responsibility delegation systems based on the revealed capability integration mechanism. (C) 2017 American Society of Civil Engineers.