Following the introduction of new guidelines in February 2006, assessments for long-term oxygen therapy are now being undertaken by respiratory nurse specialists. The key skill required is arterial blood gas sampling. This has traditionally been the role of the doctor, however by using an education and training package along with a competency-based assessment, nurses can now perform this extended role. Sarah Dodds and Graham Williamson describe a competency-based education and training programme for nurses to carry out this procedure.