There is a discrepancy in the literature as to whether cardiac patients experience deterioration in verbal learning and memory after undergoing cardiac surgery. The current study examined the executive strategy of semantic clustering in patients undergoing coronary artery bypass graft (CABG) surgery, relative to non-surgical cardiac patients and healthy controls, at baseline and post-operatively over time. Post-operatively, CABG patients demonstrated impairment in semantic clustering, relative to the control groups, which persisted at one year. Post-operative differences in semantic clustering profiles were found, with CABG patients lacking semantic clustering accrual across trials, relative to the control groups. Additionally, significantly more CABG patients were classified as "worsened" post-operatively. Deficits in semantic clustering in post-operative CABG patients are discussed in the context of an inflammatory response, heparin-induced sequelae, and microembolic strokes. The current study demonstrates the value in analyzing semantic clustering as a specific indicator of executive functioning impairment within a cardiac sample.