PRODIGY is a prescribing decision-support tool that encourages evidence-based cost-effective prescribing and supports information for patients with patient information leaflets. Following two successful pilot phases, the Department of Health has announced plans for a nation-wide rollout to all general practitioners in the UK. This paper describes the implementation and evaluation of PRODIGY Phase Two by AAH Meditel, one of the five participating GP system vendors. Based on the results and feedback from Phase One, Meditel made a number of changes to the software and training for Phase Two. The results showed Meditel's implementation of Phase Two was significantly better than the implementation of the other vendors (27% use versus 13% use), and also significantly better than its own implementation of Phase One (27% use versus 9.3% use). Patient information leaflets were issued 5.7% of the times versus 2.3% for the other vendors and 1.0% for Phase One. Detailed log files enabled the evaluation of the implementation of both phases and the software and training improvements made in Phase Two, and are recommended for the successful implementation of any clinical decision-support system project.