The use of oral anticoagulation therapy in primary care is increasing. We compared general practitioner (GP)-led oral anticoagulation monitoring with a nurse-led service involving near patient testing and computerized decision support (NPT-CDS). The nurse-led NPT-CDS service provided anticoagulation control equivalent to the traditional GP-led service, with identical mean international normalized ratio (INR) values and a nonsignificant trend towards improvement in all other parameters. Recording of indications for anticoagulation and target INR ranges were significantly improved using CDS software. For patients established on warfarin, the GP-led service was costed at £56.88 per patient per year, compared with £63.76 for the nurse-led NPT-CDS service. Patients overwhelmingly preferred the NPT-CDS service for reasons of convenience, avoidance of phlebotomy and improved dosage instructions. Performance of the NPT-CDS service within the National External Quality Assurance Scheme (NEQAS) was satisfactory. In conclusion, nurse-led oral anticoagulation utilizing NPT-CDS is an effective and acceptable alternative to traditional GP-led monitoring. The costs of an NPT-CDS service are higher, but need to be set against factors such as patient satisfaction and escalating GP workload.