Surgical data banks are used in three main ways in the recognition of surgical indications, viz., a) patient data relevant to decision making are made available without loss of time; b) experience gained in situations involving similar decisions is promptly recalled; c) an empirical basis is provided for computerized decision making. The Institut für Medizinische Datenverarbeitung of GSF in co-operation with the Surgical clinic of TUM and of the University of Munich has built up a data bank containing information on more than 60000 patients, and some of the aids mentioned above are already in routine use. Some of the aids are being tested parallel to conventional procedures.