In surgery, computer support is still of minor importance. It is the aim of this publication to outline the concept of a computer-assisted documentation system for surgical procedures, to describe the realization of the concept and to discuss the results of the evaluation. Planning of the system started in 1988 with an analysis of existing computer support at our clinic, definition of the parameters to be documented and determination of the classifications to be used, followed by a design for the system's use and a decision on hardware and software. The system is run on an IBM-compatible personal computer with three terminals, and the software used is MEDOS. The surgical procedures are documented with a four-level hierarchical classification related to the VESKA code and the internal university codes. After extensive training of the doctors, routine use commenced in 1991. Up to now 9837 operations have been documented by 35 surgeons. The system produces all necessary statistics and supports scientific studies and inquiries from individual doctors. A prospective evaluation of 300 consecutive operations demonstrated good compliance of the doctors and high data quality. To achieve optimal benefit from the use of computers it is recommended that departmental communication and documentation systems be gradually built up in surgical departments.