The internal thoracic artery (ITA) is the most important conduit for coronary artery bypass grafting. Recent evidence suggests that skeletonized ITA harvesting yields long-term outcomes inferior to those of pedicled harvesting. The aim was to investigate the impact of the ITA harvesting method on 10-year mortality and major adverse cardiovascular events. In this observational cohort study, we identified all patients from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) register who underwent isolated coronary artery bypass grafting using at least 1 ITA at Karolinska University Hospital from 2012 to 2021. The main outcome was all-cause mortality, and the secondary outcomes were a combination of myocardial infarction, repeat revascularization, heart failure, and stroke. Outcomes were ascertained using national health data registers and compared between the skeletonized and pedicled groups using weighted flexible parametric survival models. Among 3267 patients, 1657 (51%) underwent pedicled ITA harvesting and 1610 (49%) underwent skeletonized ITA harvesting. The patients' mean age was 66 years, and 15% were women. The weighted all-cause mortality incidence rate in the pedicled versus skeletonized ITA group was 2.6% (95CI, 2.2%-3.0%) versus 2.6% (95% CI, 2.2%-3.1%), respectively (hazard ratio (HR), 1.01 [95% CI, 0.81-1.27]). The weighted major adverse cardiovascular events incidence rate was 7.8% (95% CI, 7.1%-8.6%) versus 7.5% (95% CI, 6.7%-8.4%), respectively (HR, 0.94 [95% CI, 0.82-1.08]). We found no significant differences in all-cause mortality or major adverse cardiovascular events rates between the 2 ITA harvesting methods.