A reliable IT infrastructure and smoothly running IT applications are nowadays essential to every organization. Hence, the field of IT Operations Management (ITOM) has drawn much attention in practice. However, this field has hardly been subjected to academic research in the past. Therefore, organizations that are willing to professionalise their IT operations have to rely on industry standards rather than well-reasoned recommendations from academia. The predominant approach taken to ITOM in these standards is that of IT service management (ITSM). But the ideas and concepts associated with ITSM have hardly been evaluated by research so far. We have addressed this shortfall in five action research projects. This paper reports on three of these projects which had the objective in common to introduce ITSM to the organisation and that all build on four ITSM core concepts: the IT service, the IT service portfolio, the IT service catalogue, and IT service cost accounting and pricing. We found that these concepts were difficult to implement in the organisations we studied. While some of the difficulties might be due to organisational peculiarities, we found strong indications for problems being inherent to these concepts. These lead us to call for more academic attention to be paid to ITOM in general and the ITSM approach in particular. We also put forward desiderata for future research.