In this article the authors report on the evaluation of an out-of-hours telephone triage and advice service in general practice. A computer-based decision support tool was used to guide nurses in the assessment of patients and outcome for calls. Data from the computer system were analysed for all calls over a six-month period. The researchers found that the nurses were able to handle just over half the calls received by giving advice alone. Overall, the service appeared to be remarkably consistent in the decisions taken by nurses, and training and organisational issues to be considered in the future development of the service were identified.