A teleradiology system was designed for image transfer between two hospitals. One of the main challenges of the work was the user interface, which was to be easy to operate and to learn, and was equipped with useful functions for image manipulation and diagnosing. The software tools used were the Unix operating system (HP-UX v.7.0), C programming language and the X Window System (or simply X). The graphical user interface (GUI) was based on OSF-Motif standard, and it was developed by using the HP-Interface Architect. Both OSF-Motif and HP-Interface Architect are based on X. The results of the development project were installed for clinical use in the Turku University Central Hospital. The work demonstrates, that the X Window System has useful and advantageous features for radiology department's computer network environment.