Aims and objectives To identify how nurses in the past determined best practice, using the context of New Zealand, 1930–1960. Background In the current context of evidence-based practice, nurses strive to provide the best care, based on clinical research. We cannot assume that nurses in the past, prior to the evidence-based practice movement, did not also have a deliberate process for pursuing best practice. Discovering historical approaches to determining best practice will enrich our understanding of how nurses' current efforts are part of a continuing commitment to ensuring quality care. Design Historical research. Methods The records of the Nursing Education Committee of the New Zealand Registered Nurses' Association, 1940–1959, and the 309 issues of New Zealand's nursing journal, Kai Tiaki, 1930–1960, were analysed to identify the profession's approach to ensuring best practice. This approach was then interpreted within the international context, particularly Canada and the USA. Results For nearly 30 years, nurse leaders collaborated in undertaking national surveys of training hospitals requesting information on different nursing practices. They subsequently distributed instructions for a range of procedures and other aspects of nursing care to standardise practice. Standardising nursing care was an effective way to ensure quality nursing at a time when hospital care was delivered mostly by nurses in training. The reasons for and timing of standardisation of nursing care in New Zealand differed from the international move towards standardisation, particularly in the USA. Conclusions Historically, nurses also pursued best practice, based on standardising nursing procedures. Relevance to clinical practice Examining the antecedents of the present evidence-based approach to care reminds us that the process and reasons for determining best practice change through time. As knowledge and practice continually change, current confident assertions of best practice should and will continue to be challenged in future.