Background and objective Clinical guidelines recommend the use of beta‐blockers and other cardiovascular prevention drugs in patients with acute coronary syndrome (ACS). Studies in several countries have found that beta‐blockers are underused in patients with chronic obstructive pulmonary disease (COPD) and co‐morbid heart disease, although most have only examined use in subgroups of patients. We undertook a nationwide follow‐up study in New Zealand to describe the use of beta‐blockers and other cardiovascular prevention drugs in patients with COPD and ACS. Methods National health and pharmaceutical dispensing data were used to derive the study cohort, identify patients who were admitted to hospital with ACS and/or heart failure before cohort entry and during follow‐up, and ascertain drug use. Results The study cohort included 83 435 patients aged ≥45 years, with 290 400 person‐years of follow‐up. Among 2637 patients with ≥1 ACS admission during follow‐up, only 56.6% received a beta‐blocker in the 6 months following the first admission, while 87.7% and 81%, respectively, received aspirin and a statin. Patients with higher COPD severity were less likely to receive a beta‐blocker than those with lower severity, as were those with no history of previous ACS and/or heart failure. Conclusion Use of beta‐blockers following an ACS admission was much lower than expected based on the findings of general audits of ACS management in New Zealand. Along with the higher proportions using aspirin and statins, and the differences in beta‐blocker dispensing by COPD severity, this suggests a particular reluctance to prescribe beta‐blockers to patients with COPD.