Background: Accurate perception of cardiovascular risk is important if people with established, or at high risk of, coronary heart disease are to engage in risk-reducing behaviours. Aim: This study aimed to determine whether the risk perception of patients undergoing a percutaneous coronary procedure was related to their subsequent engagement in risk-reducing behaviours. Methods: Using a prospective correlational design, patients presenting to a tertiary referral hospital in Sydney, Australia for an interventional cardiology procedure were surveyed at baseline and again at six months. Data collected included demographic and clinical information, relative risk perception (RRP-2), psychological status using the Hospital Anxiety and Depression scale and the Perceived Stress Scale, and physical activity using the Physical Activity Scale. In addition, data on medication adherence and cardiac rehabilitation enrolment were collected at the six-month follow-up. Results: The study cohort consisted of 220 participants. Statistical analysis revealed a reduction in anxiety (p<0.001), depression (p =0.004) and stress (p <0.001), and an increase in physical activity engagement (p <0.001) from baseline to six-month follow-up. Higher risk perception scores at baseline predicted an increased likelihood of enrolment in a cardiac rehabilitation programme (p =0.01) and adherence to medication regimen (p =0.007). Conclusions: This study revealed an overall underestimation of risk perception among a sample of 'high risk' cardiac patients admitted to hospital for an interventional coronary procedure, with those who reported lower risk perception being less likely to attend cardiac rehabilitation and less likely to adhere to their medication regimen.