During 1987 a system for the computer-aided diagnosis of abdominal pain was introduced on a trial basis in seven district health authorities in the North Western (NW) Region. Despite good reports of the system from other areas, by the end of a 12-month period only two of the seven districts continued to use it in the routine management of patients. A study was undertaken to determine the difficulties that had been encountered and the way in which these had hindered successful implementation of the system. Information was obtained by interview with key personnel involved in the trial, which included the chief executive in each district, a consultant designated as responsible for the system and clerical staff. The study identified three main factors undermining the implementation of the system: a lack of consultant support; the negative attitude of junior doctors; and inadequate clerical support.