In-service education (ISE) in nursing is teaching that occurs in the workplace. Internationally, ISE activities have been evident in nursing for many years because it has been seen as a convenient and cost-effective way to deliver education to nurses with minimal disruption to staffing levels and the delivery of patient care. ISE-related literature was sought to address the aim of tracing development and focus of nursing ISE in New Zealand. A key finding of this literature review is that ISE has been adapted in New Zealand and internationally to meet the demands of evolving nursing practice, and for this reason it remains relevant and essential to nurses. The embeddedness of ISE within clinical environments also supports its relevance. Future research is called for to establish which aspects of ISE are critical to ensuring its ongoing success.