An increasing number of people seek primary care at casualty or accident and emergency departments of hospitals. A questionnaire was completed by patients attending for primary care at an Australian hospital. The study aimed to determine why patients chose the hospital for their medical care, whether patients triaged to the Primary Care Unit differed from patients triaged to the Casualty section of the Accident and Emergency Department, and whether the characteristics of patients attending at daytime differed from those attending out of hours. There were no significant differences between daytime and out-of-hours attenders according to sex or whether born in Australia or not. More children presented at night or at the weekend; more older people presented by day. There were more single, divorced, separated and widowed patients among the daytime attenders. Daytime attenders had significantly lower incomes than out-of-hours attenders, were less likely to have a local general practitioner or full health insurance: most had a health care card and cost may have been a factor in their attendance. Out-of-hours attenders who had a local general practitioner appeared to be unaware of any deputizing services or had rejected them in favour of the hospital service.