Safe levels of anticoagulation are normally considered to be achieved if patients are maintained within their therapeutic international normalized ratio (INR) range for 70% or more time, but evidence in the United Kingdom suggests that this is often not attained. Recently, alternative models in the management of out-patient anticoagulation have been investigated with favourable results. We report on a study which compared a consultant anticoagulant service (CAS) with a nurse specialist service (NSAS). A sequential design was used with data collected on the consultant run service (CAS), followed by similar data on a NSAS over two 6 month periods. Two patient groups were recruited: those newly referred (group A) and those on long-term treatment (group B). Outcomes were the proportion of time patients spent within INR range, documentation of relevant clinical details, number of drugs taken which may adversely interact with and/or inhibit haemostatic function and patient knowledge. The results indicate that the NSAS was as good as the CAS in maintaining therapeutic control and better at documenting relevant clinical details in reducing the number of drugs taken which may adversely interact with and/or inhibit haemostatic function and in improving some aspects of patient knowledge.