The Australian health care system is continually under increasing pressure due to a rapidly ageing population, high prevalence of chronic illnesses, and ever increasing expectations in service delivery. This is barely manageable in the short-term and projections indicate that in the long-term this will present a significant challenge. One approach to reduce this unsustainable demand on services and associated costs has been to attempt to shift service delivery from the acute to the primary health care sector. It is thought that such a shift will reduce costs and demand on hospitals and alleviate the distress that patients with chronic conditions experience from being hospitalised due to their condition reaching a level requiring acute care/intervention. It has been estimated that nearly 10% of admissions to hospital are potentially preventable representing a significant cost to the Australian health care system and distress for patients. For common chronic conditions such as diabetes, congestive heart failure and asthma, it is thought that a shift in focus from acute to the primary care sector can delay or prevent the onset of complications and reduce potentially preventable emergency department (ED) presentation and hospitalisations. This theory surrounding so called ?ambulatory care sensitive chronic conditions? has been the driver of many policies aimed at increasing long-term ongoing, rather than sporadic and episodic, contact with a General Practitioner (GP). However, despite multiple large-scale initiatives and substantial investment of the Federal government into addressing this issue, currently there is very little evidence of the relationship between continuity of primary care and a reduction in potentially preventable hospitalisations. In the Australian context, knowledge about the influence of patterns of GP contact on ED visits and hospitalisation for a range of chronic conditions will be used to evaluate the effect of shifting the focus from acute to primary care as a prevention and cost saving strategy. This will provide essential inputs to economic models of health gains and cost savings derived from existing and future primary care strategies.