This paper proposes a semi-automatic approach to extract information stored in a HL7 Clinical Document Architecture (CDA) and transform them to be loaded in a Data Warehouse for secondary purposes. It represents a suitable solution to facilitate the design and implementation of Extract, Transform and Load (ETL) tools that are considered the most time-consuming step of the data warehouse development process. The implementation of this framework is also proposed adopting the XSLT style sheet language that converts an original CDA XML-based document to an output XML document that can be easily loaded in the Data Warehouse. A case study is also provided to demonstrate the feasibility of the approach proposed.