The chapter examines the changes to the dominion of nursing work on active service overseas. The chapter first explores the extensions to the nursing role, most particularly the care of wounds and burns. This is followed by a discussion of the expansion of nursing duties into those that had hitherto been the domain of medicine. These roles include the commencement and management of blood transfusions, surgical work and anaesthesia. Finally the chapter considers ‘new work’, the most critical of which was the administration and use of penicillin. The constantly shifting requirements of war nursing prevented Army nurses from remaining in a professional comfort zone of accepted roles and regimes. The experience of living with uncertainty may have caused anxieties for some, but the active participation in new treatment modalities suggests that nurses who went to war were keen to move beyond the normal boundaries of nursing practice and many relished the opportunity to do so. The chapter argues that the developments in practice and the increased confidence nursing sisters displayed with this new work altered their working relationships with medical officers from one of deference to one of collegiality, enabling more productive decisions for their soldier-patients’ care.