OBJECTIVES: To determine factors associated with repeat attendance at emergency department (ED) of a secondary care hospital in Singapore. METHODS: An analysis of data from the EDWeb of all patients who attended ED between January 1, 2005 and December 31, 2007 was performed. Variables considered in the analysis were age, gender, race, date of attendance, and diagnosis based on ICD-9CM code. Frequency of ED attendance was categorized into index attendance, repeat attendance and high impact attendance. Index attendance refers to the first visit by the patient to the ED. Repeat attendance refers to more than one visit by the same patient. High impact attendance refers to patients with >5 ED visits. RESULTS: There was a total of 141,642, 142,820, 160,096 ED attendances in 2005, 2006, and 2007, respectively. Of these, 22-24% were by elderly patients (65+ years), and 27%-28% were repeat attendance. Repeat attendance rate increased with age, with highest rates among those aged 75+ years (36%-38%) and significantly higher among young males, older females, and those presenting with chronic obstructive pulmonary disease, respiratory infections, pneumonia, diabetes and heart failure. High impact attendance comprised 7-11% of total attendance and have increased by 12% among persons aged 75+ over the period 2005-2007. Majority (60%) were males. CONCLUSIONS: Repeat attendance constitute more than one fourth of total ED attendance and is marked among the elderly. Singapore's aging population with its complex health needs is likely to make up an increasing proportion of the workload of ED staff in the coming years.