As part of the Medical Informatics Initiative (MII), data integration centers (DICs) have been established at 38 university and 3 non-university locations in Germany since 2018. At DICs, research and healthcare data are collected. The DICs represent an important pillar in research and healthcare. They establish the technical, organizational, and (ethical) data protection requirements to enable cross-site research with the available routine clinical data.This article presents the three main pillars of DICs: ethical-legal framework, organization, and technology. The organization of DICs and their organizational embedding and interaction are presented, as well as the technical infrastructure. The services that a DIC provides for its own location and for external researchers are explained, and the role of the DIC as an internal and external interface for strengthening cooperation and collaboration is outlined.Legal conformity, organization, and technology form the basis for the processes and structures of a DIC and are decisive for how it is integrated into the healthcare and research landscape of a location, but also for how it can react to national and European requirements and act and function as an interface to the outside world. In this context and with regard to national developments (e.g., introduction of the electronic patient file-ePA), but also international and European initiatives (e.g., European Health Data Space-EHDS), the DIC will play a central role in the future.