Chronic obstructive pulmonary disease (COPD) and atrial fibrillation (AF) are common comorbidities in patients with acute myocardial infarction (AMI) and are associated with adverse cardiovascular outcomes. However, the impact of their coexistence on long-term post-AMI outcomes remains unclear. This study aimed to investigate the long-term effects of COPD and AF on AMI survivors. This retrospective cohort study analyzed data from consecutive AMI hospitalizations between 1 January 2002 and 31 October 2017. Patients were categorized into four groups based on the presence or absence of COPD and AF. The primary outcome was all-cause mortality up to 10 years post-discharge. Multivariate survival models were used to assess independent associations. A total of 15,449 AMI survivors (mean age 66 ± 14 years, 30% female) were included, of whom 1386 (8.9%) had COPD, 2547 (16.5%) had AF, and 376 (2.4%) had both conditions. Over a median follow-up of 7.7 (IQR 3.3-10) years, 44.7% of the patients died. COPD (AdjHR = 1.89, 95% CI: 1.74-2.05), AF (AdjHR = 1.39, 95% CI: 1.31-1.48), and coexistence of both conditions (AdjHR = 1.82, 95% CI: 1.61-2.04) were associated with an increased risk for mortality ( < 0.001 for each). However, in patients with both conditions, the mortality risk was comparable to that of COPD alone. While both COPD and AF are associated with increased long-term mortality after AMI, COPD appears to be the primary independent driver of this risk. These findings underscore the need for proactive screening and individualized management in this high-risk population.