Data warehouses (DWs) have become one of the major IT-investments during the last decades and in order to fully exploit the potential of data warehouses, more and more organizations are acquiring and integrating external data into their star-schemas. However, the literature covering external data acquisition and integration is limited. Therefore, in this paper the results of an interview study conducted among banking organizations are presented. The study aimed at identifying different approaches for acquiring and integrating external data into DWs. The results show that there are many different approaches for the acquisition and integration, depending on the purpose and structure of the data being acquired. In addition, the most common external data acquisition and integration process is presented and discussed.