Stroke is the second most common cause of death worldwide and represents a significant burden on the health care sector. Transient ischaemic attacks (TIAs) identify high-risk patients and rapid best medical management reduces stroke risk by 80%. The TIA/Stroke electronic decision support (EDS) tool is designed to help general practitioners to realise this potential risk reduction. This study aims to test the efficacy of the EDS tool with regard to stroke reduction, assess any risks associated with EDS use, and establish costs of EDS use compared with usual management. The study design is a randomised controlled trial comparing EDS use versus usual care over a 12-month enrolment and a three-month follow-up period. This is the first formal evaluation of a TIA/Stoke EDS and, within 3 years of study commencement, its results will inform policy and practice relating to use of this TIA/Stroke EDS in New Zealand.