The paper presents a new theoretical framework for coordinating an inter-unit collaborative service process towards a joint customer. The common service process is itself presented as a central coordination mechanism. It defines how tasks and responsibilities are shared between the collaborating units. The framework presents the factors supporting cooperation between the units, the prerequisites of the common service process, and the ways of coordination suitable for inter-unit cooperation. The framework is developed through a single-company longitudinal, qualitative case study that consists of three action research projects. Keywords Coordination, collaboration, service process, case study, action research