Various studies have implicated a potential association between candidate gene polymorphisms and postoperative cognitive dysfunction, yet corroborative studies are lacking. We investigated the variants in genes encoding platelet glycoprotein-IIIa and apolipoprotein-E and their relationship with postoperative cognitive dysfunction one year after cardiac surgery. A total of 155 patients were studied; neuropsychological testing demonstrated cognitive dysfunction in 31 (20%) patients at one-year follow-up. ⋯ The apolipoprotein E-ε4 allele was present in 9 (29%) and 24 (19%) patients with and without cognitive dysfunction, respectively, p = 0.24. Both the Pl(A2) and apolipoprotein-ε4 alleles were present together in 6 (19%) and 5 (4%) patients with and without cognitive dysfunction, respectively, p = 0.003. Validation of these findings is required in age-adjusted non-surgical controls.