BACKGROUND Hyperglycemia is associated with poor postoperative outcomes after carotid endarterectomy. This retrospective study examined the effect of lactated Ringer's and normal saline solutions on intraoperative blood glucose control in diabetic patients undergoing carotid endarterectomy. METHODS The anesthetic and surgical records of type 2 diabetic patients who underwent carotid endarterectomy and received either lactated Ringer's solution or normal saline exclusively during the case were reviewed, and 20 patients were randomly selected from each group for further analysis. The outcome of interest was preoperative to postoperative change in blood glucose. RESULTS The preoperative to postoperative mean changes in glucose for the normal saline and lactated Ringer's groups were 34.4 ± 70.32 mg/dL and 64.5 ± 61.38 mg/dL, respectively. This slight difference in the mean change in glucose between the 2 groups was not statistically significant (P=0.157). CONCLUSION Lactated Ringer's solution does not appear to cause a significant change in the mean blood glucose levels in diabetic patients undergoing carotid endarterectomy compared to patients receiving normal saline. Randomized controlled trials are needed to further determine whether lactated Ringer's solution adversely affects glucose control in diabetic surgical patients.