Purpose <p>Oral health and its impact on general well-being is acutely evident with a cancer diagnosis. Most cancer treatments will affect the oral environment, with poor oral health having the potential to negatively impact cancer treatment outcomes.</p> Methods <p>This retrospective study included 1500 patients referred for dental examination prior to cancer therapy at the Peter MacCallum Cancer Centre, Australia, between January 2017 and August 2019. Demographic characteristics, cancer diagnosis, and baseline oral health information were recorded.</p> Results <p>Patients were referred from the head and neck tumour stream (56%), haematology (27.7%), breast and genitourinary (6.1%), and others (9.7%). Of the patients who required dental treatment 49% required a dental extraction prior to their cancer treatment to optimise oral health. Head and neck cancer patients presented with poorer oral hygiene and required more dental extractions than other patient groups (<i>χ</i>² = 17.59, <i>p</i> = 0.00003).</p> Conclusions <p>Baseline oral health for cancer patients was below expected compared with the Australian average. Dental treatment was necessary for more than half of patients to reduce infection risk and improve function and quality of life during and following cancer treatment, highlighting the essential role of oral health clinicians in the multidisciplinary team.</p>