Aims The aims of this study are to identify the proportion of ACS patients using an ambulance to transport to hospital and to explore the factors influencing mode of transport. Methods A retrospective, observational cohort design was utilised in this study. Data concerning cases of ACS in a university hospital over a 9-year period was obtained from the Coronary Heart Attack Ireland Register. Descriptive statistics were used to detail demographic and clinical data, as well as to establish the proportion of ambulance usage among ACS patients. Chi-square and t-tests were used to differentiate between groups at baseline. Factors influencing mode of transport were analysed by binary logistic regression. Results 4,229 cases were obtained. Exclusion and inclusion criteria were applied, leaving 1,964 cases for overall analysis. 533 (27%) patients directly used an ambulance, 1,098 (56%) patients presented initially to their GP while 333 (17%) went directly to A&E. Logistic regression showed that age, clinical factors, smoking status and diagnosis each had a statistically significant effect on ambulance usage. Conclusions Ambulance services are underutilised by ACS patients, despite clear benefits of their use. Several factors impacted patients' mode of transport. Knowledge of these is essential in guiding future awareness campaigns to promote ambulance usage in ACS.