Background: The optimal antiplatelet therapy for patients with chronic kidney disease (CKD) undergoing coronary artery bypass graft surgery remains unknown. Methods: This post hoc analysis of the Ticagrelor in Coronary Artery Bypass (TiCAB) trial examined the efficacy and safety of ticagrelor vs aspirin in patients with and patients without CKD. The primary endpoint was major adverse cardiac and cerebrovascular events (MACCE), namely, the composite of cardiovascular death, stroke, myocardial infarction, or revascularization at 1 year after coronary artery bypass graft surgery. Secondary endpoints included individual components of the primary endpoint, all-cause death, and major bleeding. Results: Chronic kidney disease was present in 276 of 1843 randomized patients (15%). Patients with CKD vs patients without CKD had higher 1-year rates of MACCE (13% vs 8.3%, hazard ratio [HR] 1.63; 95% confidence interval [CI], 1.12 to 2.39; P =.01) and major bleeding (5.6% vs 3.1%, HR 1.84; 95% CI, 1.03 to 3.28; P =.04). The 1-year rate of MACCE was increased with ticagrelor vs aspirin in patients with CKD (18.2% vs 8.9%, HR 2.15; 95% CI, 1.08 to 4.30; P =.03), but not in patients without CKD (8.5% vs 8.1%, HR 1.05; 95% CI, 0.74 to 1.49; P =.79; Pinteraction =.067). There was no difference in the 1-year rate of major bleeding with ticagrelor vs aspirin in patients with CKD (6.6% vs 4.7%, HR 1.44; 95% CI, 0.52 to 3.97; P =.48) and patients without CKD (3.3% vs 2.9%, HR 1.14; 95% CI, 0.64 to 2.01; P =.65). Conclusions: Among patients with CKD and coronary artery bypass graft surgery, those who received ticagrelor had a higher incidence of MACCE but a similar incidence of major bleeding compared with those who received aspirin.