The purpose of this research is to identify typical professional and occupational groups in service-intensive projects, and illustrate the inbuilt tensions among them through the lens of institutional theory. The cases used for the study are a wind turbine business and a content management system project business. Our findings suggest that there are two professional groups (problem solvers, technology developers) and two occupational groups (lead generators, relationship developers) involved in these businesses. More importantly, their intergroup tensions are related to different institutionalized logics toward the conception of time (project temporality) and prioritization of different aspects of business (primarily commercial or technical issues) that become manifested in stereotypes, perceptions of trust, internal politics and lack of cooperation. Together, we call these institutional logics the project ethos of each group. Our findings contribute to the research on project management by illustrating the organizational challenges of service-intensive projects.