In a period where digitization rapidly influences the corporate world, Cloud Computing (CC) has emerged over the past years as well. CC refers to offering hardware, software, and data by a provider over a network and can benefit organizations enormously regarding cost efficiency, operational excellence, and innovation. Software-as-a-Service (SaaS), a delivery model of CC, allows organizations to deploy and use complete applications over the internet, which are managed by an external provider. The use of SaaS can bring firms several benefits, such as scalability, transparency of costs, access to high-end applications, and avoidance of up-front costs. However, it is unclear how the migration to SaaS impacts the IT-department on an organization level, and how IT-departments should adapt to perform in a SaaS-environment. This research contributes to this knowledge gap by investigating which resources and capabilities of the IT-department should change for the IT-department to perform. Propositions were formulated based on a literature research and a questionnaire, and empirical data was collected by means of a case study research. The results show that financial assets, technological tools, organizational structure, management systems, skills, knowledge, organizational culture, contractual governance, and relational governance are important resources of the IT- department, that should change in order to perform. The insights gained from this study can support organizations’ decision- makers improving the organization of the IT-department when migrating to a SaaS-environment.