An interface was created between the Department of Defense's hospital information system (HIS) and its two picture archiving and communication system (PACS)-based radiology information systems (RISs). The HIS is called the Composite Healthcare Computer System (CHCS), and the RISs are called the Medical Diagnostic Imaging System (MDIS) and the Digital Imaging Network (DIN)-PACS. Extensive mapping between dissimilar data protocols was required to translate data from the HIS into both RISs. The CHCS uses a Health Level 7 (HL7) protocol, whereas the MDIS uses the American College of Radiology-National Electrical Manufacturers Association 2.0 protocol and the DIN-PACS uses the Digital Imaging and Communications in Medicine (DICOM) 3.0 protocol. An interface engine was required to change some data formats, as well as to address some nonstandard HL7 data being output from the CHCS. In addition, there are differences in terminology between fields and segments in all three protocols. This interface is in use at 20 military facilities throughout the world. The interface reduces the amount of manual entry into more than one automated system to the smallest level possible. Data mapping during installation saved time, improved productivity, and increased user acceptance during PACS implementation. It also resulted in more standardized database entries in both the HIS (CHCS) and the RIS (PACS).