OBJECTIVE To determine the reasons for choosing between primary care out of hours centres and accident and emergency (A&E) departments for patients with primary care problems. METHODS Interviews using a semistructured approach of samples of patients attending A&E departments and general practitioner (GP) out of hours centres for primary care problems. RESULTS 102 patient interviews were undertaken. Sixty two per cent of A&E attenders were unemployed compared with 41% of out of hours attenders. White people were more likely to attend A&E departments and Asians the out of hours centre (p<0.01) and unemployed were more likely to attend A&E departments (70% v 30%). Some 46.3% of A&E department attenders had not contacted their GP before attending; 81.3% of first time users of the out of hours centre found out about it on the day of interview. Those attending A&E thought waiting times at the out of hours centre would be 6.3 hours (median) compared with a median perceived time of 2.9 hours by those actually attending the out of hours centre. Actual time was actually much less. CONCLUSIONS Once patients have used the GP out of hours centre they are more likely to use it again. Education should be targeted at young adults, the unemployed and white people. Patients should be encouraged to contact their GP before A&E department attendance for non-life threatening conditions. Waiting time perception may be an important reason for choice of service.