Background: Peripheral intravenous cannula is often a first line invasive intervention for patients in the emergency department. It is used to facilitate blood sampling, deliver essential fluids, blood products and medication. However, the insertion and use of the peripheral intravenous cannula is not without complication. This study surveyed the number of peripheral intravenous cannulas inserted in the emergency department and identify the level of and reason for use. Methods: A cross-sectional study was conducted in the emergency department of a large tertiary hospital in Queensland. Descriptive and inferential statistics were used to describe peripheral intravenous cannula use and to explore associations. Results: Of the 224 patients assessed, 159 (71%) had at least one peripheral intravenous cannula inserted in emergency department. Of the 159 peripheral intravenous cannulas inserted, 54 (34%) remained unused while the patient was in the emergency department. For patients classified as Australasian Triage Scale categories 3, 4 and 5, 40% of peripheral intravenous cannulas remained unused. Overall, poor documentation was observed with 29% of peripheral intravenous cannulas insertions not documented at all. Conclusion: This study identified a high proportion of unused peripheral intravenous cannulas in the emergency department and inadequate documentation. An intervention to promote best practice, raise awareness of the risks of peripheral intravenous cannulas use, possible alternatives therapies, and improve documentation is required.