OBJECTIVES: Advance care planning (ACP) is a process of planning for future health and personal care when the person preferences are made known so that they can guide the decision making at a future time when that person cannot make or communicate his or her decisions. This is particularly relevant for the population with high risk of dementia because the disease progression results in losing decision-making ability. ACP may also result in savings to the health care system as futile medical treatment can be avoided. This study aims to assess the impact of delivering an intervention to boost rates of ACP in Australia through a primary care intervention in the dementia context.  METHODS: A decision analytic economic model was constructed to identify the impact of introducing a intervention to provide ACP on the Australian Health Care system, in particularly for those who were diagnosed with dementia. The study population were adults aged 65 years and over. The stability of the results was thoroughly tested in sensitivity analyses. RESULTS: The results showed that over a lifetime, compared to the current situation, an ACP program is less costly in the dementia context. The cost saving was generated from a lower rate of hospital-based end-of-life care for patients who had an ACP. Sensitivity analyses highlighted the importance of the ACP coverage, the hospitalisation rate at end-of-life, and the ACP compliance rate. The optimal outcome of an ACP program can be achieved with a system-wide approach that allows a relatively flexible design to accommodate different life situations.  CONCLUSIONS: Introducing a primary health care intervention to increase rates of older people participating in ACP can be a cost-effective way to allows individuals to benefit from having the type of health care they desire while reducing potential family conflict, and removing stress about medical decision making at times of emergency.