Objectives <p>To investigate the prognostic value of lipomatous metaplasia (LM) in patients after myocardial infarction (MI) and to explore potential influencing factors of LM.</p> Materials and methods <p>A total of 1702 (mean age 59.3 ± 10.27 years, 86.08% men) patients with a history of MI who underwent coronary CT angiography (CCTA) examinations were retrospectively enrolled. The clinical endpoints were major adverse cardiovascular events (MACE). A subgroup of 240 patients who underwent CCTA and cardiac magnetic resonance (CMR) examinations within a 14-day interval was analyzed to compare the prognostic values of LM and CMR parameters and to explore influencing factors of LM.</p> Results <p>MACE occurred in 395 (23.21%) patients during a median follow-up of 45.5 months. In the entire cohort, the prevalence of LM was 46.71% on CCTA; in the subgroup, it was 51.25% on CCTA and 21.67% on CMR. LM remained a significant outcome predictor (hazard ratio (HR) 1.39, 95% confidence interval (CI) 1.12–1.73; <i>p</i> = 0.002) in the multivariable model. In subgroup analysis, LM on CCTA (HR 1.83, 95% CI 1.09–3.08; <i>p</i> = 0.023) was a stronger outcome predictor than all CMR parameters. Revascularization history (odds ratio (OR) 2.833, <i>p</i> = 0.006), number of diseased coronary arteries (CA) (OR 0.556, <i>p</i> = 0.006) and infarct size (OR 1.094, <i>p</i> = 0.003) remained associated with LM in the multivariable model.</p> Conclusion <p>LM was a significant outcome predictor in patients after MI and was stronger than CMR functional parameters and infarct size. Revascularization, infarct size and fewer diseased CA may be associated with LM development.</p> Critical relevance statement <p>Lipomatous metaplasia (LM) was a common complication following myocardial infarction (MI) that increased with infarct age, identifying LM and integration of LM assessment into risk stratification models for post-MI patients may be important for clinical strategy decisions.</p> Key Points <p><UnorderedList Mark="Bullet"> <ItemContent> <p>Lipomatous metaplasia was a common complication that increased with infarct age.</p> </ItemContent> <ItemContent> <p>Lipomatous metaplasia was a significant outcome predictor in patients after myocardial infarction, stronger than CMR functional parameters and infarct size.</p> </ItemContent> <ItemContent> <p>Revascularization procedure, infarct size and fewer number of diseased coronary arteries were associated with the presence of lipomatous metaplasia.</p> </ItemContent> </UnorderedList></p> Graphical Abstract <p></p>