Objective: The objective of this study is to describe the trends and characteristics of short-term and frequent representations to EDs in New South Wales, Australia. Methods: This was a retrospective analysis of a linked population-based registry of ED representations in New South Wales, conducted as part of the Demand for Emergency Services in Years 2010-2014 project. Trend analysis of unplanned representations to ED within 3days of discharge from ED, readmission to an in-patient unit within 30days of index in-patient admission from ED and demographic data and trends for frequent and very frequent ED presenters is discussed. Results: A total of 10798797 ED presentations were identified from 4188283 individual patients. Within 1year, 48.9% of ED presentations had a previous presentation, and 4.9% had represented within 3days of a previous presentation. The readmission rate within 30days was 2.8%, the proportion of frequent (representing 5212 [0.1%] individual patients) and very frequent representations (representing 1186 [0.03%] individual patients) were 1.7% and 1.0%, respectively. The overall rate of representations within 3days has decreased from 5.1% in 2010 to 4.7% in 2014 (P<0.001). The rate of readmissions within 30days has increased from 2.4% in 2010 to 3.1% in 2014 (P<0.001). Conclusions: In this population-based study, short-term representations were highest in the infant patient population, in-patient readmission rates were highest in the elderly and very frequent representations to ED were characterised by middle-aged patients with mental health or drug and alcohol related presentations.