Our study aimed at developing a computer-based simulation model for the consultation process in general practice. The model was developed in the computer language COM-CATS and makes use of an IBM-compatible personal computer with an automated diasprojector attached. A feasibility study comprised 122 general practitioners (108 male and 14 female), participating in the 6th Nordic Congress of General Practice (Aarhus, Denmark, 1989). All participants were given a short introduction to the patient and his symptoms, but all further information was optimal and selected by the doctor. There was a large variation in practice patterns of the general practitioners. Their actions were, however, performed selectively, i.e. a few tests were requested by most doctors and none of the doctors performed large numbers of tests. The great advantage of the computer-model in research into clinical decision-making is that it allows for a standardization of the clinical situation, gives the doctor an opportunity to select between optional information, and permits an automatic gathering of huge amounts of information about the decision-making process.