This thesis considers standardizing service requirement specification for IT sourcing. The potential benefits a standardization of service requirements writing combined with Scania IT:s developing strategy have created a need for an investigation about how requirements standardization for IT sourcing could be done. This thesis is built upon three different approaches, requirements engineering, service oriented requirement engineering and best practices. Combined, these different approaches comprise the theory model RSB that will be used in the requirements standardization work. The strategies for collecting data, the authors choose embedded case study. The main problem at Scania IT regarding requirements specification in sourcing is the absence of a standard. The service requirements specifications varies in quality and execution, which causes communication problems. In order to standardize the requirements specification, the authors of this thesis have developed a standardization model consisting of three phases. A template is developed and presented in this thesis, the template is also included in the standardization phases model. The template created in this thesis, based on the RSB-model combined with the empirics, shows how a standard template can be designed. This study also suggests a three-phase model for working with standardization in the future. The standardization model suggest a requirements management software connected to a database.