Few (conflicting) studies have quantitatively assessed neurocognitive effects of deep hypothermic circulatory arrest (DHCA). We assess neurocognitive function quantitatively before and after DHCA in comparison with non-DHCA patients.Sixty-two aortic surgical patients underwent a battery of neuropsychometric tests, both preoperative and postoperative, evaluating multiple aspects of memory, processing speed, executive function, and global cognition. Thirty-three patients did not require DHCA, and 29 underwent DHCA as the sole means of cerebral protection. Neurocognitive deficit was defined as greater than 20% decline in 2 or more cognitive areas. Preoperative and postoperative test scores, as well as incidence of neurocognitive deficit, were compared within each group, and between the non-DHCA and DHCA groups.There were no significant differences in the postoperative versus preoperative scores in any cognitive area tested between DHCA and non-DHCA groups. There was also no difference between the 2 groups in incidence of neurocognitive deficit; 13 non-DHCA, 11 DHCA (p = 1.00). In addition, there was no correlation between time under DHCA and incidence of neurocognitive deficit. Within both groups, there was a decline in memory in the areas of acquisition, retention, and delayed recall. Within the DHCA group, recognition was also affected.While cardiac surgery had some effects on memory, overall neurocognitive function was well preserved and not different between DHCA and non-DHCA patients. Time under DHCA up to 40 minutes was also found to be safe neurocognitively. This study provides strong evidence that straight DHCA effectively preserves neurocognitive function.