Background: Periodontal disease is a risk factor for atherosclerotic cardiovascular disease and it is recommended internationally that patients with cardiovascular disease should engage in preventative oral health practices and attend regular dental care visits. This study aimed to explore the oral health status, behaviours and knowledge of patients with cardiovascular disease. Methods: A cross-sectional questionnaire containing 31 items was administered to patients with cardiovascular disease from cardiac rehabilitation and outpatient clinics in Sydney Australia in 2016-2017. Results: Of the 318 patients surveyed, 81.1% reported having at least one oral health problem. Over a third (41.2%) of participants had not seen a dentist in the preceding 12 months and 10.7% had received any oral healthcare information in the cardiac setting. Those with valvular conditions were more likely to have received information compared to those with other cardiovascular conditions (40.6% versus 7.4%, p < 0.001). Only half of the participants had adequate oral health knowledge. Conclusions: Despite a high incidence of reported oral health problems, many patients lacked knowledge about oral health, were not receiving oral health information from cardiac care providers and had difficulty accessing dental services. Further research is needed to develop oral health strategies in this area.