BACKGROUND: Chronic coronary total occlusions (CTO) represent a therapeutic challenge, and results of randomized clinical trials and observational studies comparing conservative treatment versus percutaneous coronary intervention (PCI) are underpowered. AIMS: To assess myocardial infarction (MI) and all-cause mortality in consecutive patients with CTO lesions. METHODS: Using data from the West Denmark Heart Registry, patients with chronic coronary syndrome and a 100% occluded vessel by invasive coronary angiography (ICA) were identified. Patients were stratified according to PCI within 90 days. Five-year risk of MI and all-cause mortality was calculated using cause-specific Cox-models and g-formula methods. Subsequently, models were stratified on sex, diabetes, estimated glomerular filtration rate above 60 mL/min, procedure before 2012, and history of cardiac surgery. The risk was calculated for patients who did not experience MI or death within 30 days of the initial ICA. RESULTS: A total of 7675 patients were included in the study, of whom 3129 patients underwent PCI, and 4546 patients were treated conservatively. PCI- and conservatively treated patients had comparable risks of MI (13.1% [95% confidence interval [CI] 12.0%-14.3%] for patients who underwent PCI vs. 13.4% [95% CI 12.4%-13.4%] for patients who received conservative treatment). For all-cause mortality, results were 14.4% (95% CI 13.3%-15.5%) versus 18.9% (95% CI 17.8%-20.0%), respectively. Results were consistent across subgroups. However, CTO-PCI-treated patients with previous heart surgery were at higher risk of MI. CONCLUSIONS: Patients who underwent CTO-PCI had a comparable 5-year risk of MI and lower all-cause mortality as compared to conservatively treated patients.