This paper examines trends in potential 'primary care' presentations at emergency departments (ED), comparing these with other ED presentations and to primary care attendances in the community. The study draws on EDIS data (Emergency Department Information System), which, at December 2005, covered 76% of attendances in New South Wales, and from Medicare Australia MBS data. Annual counts of potential primary care presentations to EDs are compared with those of other ED presentations and to primary care presentations in the community. Changes in the percentage of ED presentations that are potentially for primary care are examined, as are changes in the percentage of total primary care presentations seen in EDs. Trends in age standardised presentation rates are also calculated for each of the three series. Primary care presentations at EDs increased marginally in the period under consideration, as did primary care presentations in the community. There was a substantial increase in other ED presentations. The proportion of ED presentations potentially for primary care decreased over the period. The proportion of primary care presentations seen in EDs and the proportion seen in the community changed little. Decline in the proportion of potential primary care presentations to EDs may have been impacted by new guidelines for the application of triage categories in 2001. However, trends over time do not show acute alterations and they continue to hold for the subsequent period after introduction of new guidelines. Primary care presentations at EDs are not responsible for recent changes to ED overcrowding in New South Wales, at least not for hospitals covered in the EDIS database. Future research might consider more specific trends in rural EDs.