Several studies have demonstrated that a sizeable proportion of patients undergoing coronary artery bypass graft (CABG) demonstrate persistent declines in cognitive functioning. However, several important questions remain regarding cognitive changes following CABG. First, can patients vulnerable to cognitive decline after CABG be identified, providing valuable information that can be factored into clinical decisions? Second, the specificity of CABG as a cause of cognitive decline, when compared to other coronary procedures such as percutaneous coronary interventions, has not been established. Third, what mechanisms account for the neurocognitive decline after CABG? Several mechanisms have been proposed to lead to post-CABG neurocognitive deficits, including pre-CABG neurocognitive deficits, physiological injury, psychosocial factors, and/or the patient's perceptual processes. Finally, no study has demonstrated that cognitive changes, as measured by neuropsychological tests, have ecological validity. Specifically, behavioral sciences research is needed to demonstrate that measured cognitive changes significantly impact health status independent of other risk factors.