Abstract Objective To evaluate use of continuous glucose monitoring (CGM) technology in the perioperative setting by comparing CGM with concurrent point of care fingerstick blood glucose (BG) or arterial BG values, as indicated, in patients with hyperglycemia and/or diabetes mellitus undergoing surgery. To assess if grounding device correlated with loss of CGM signal as a prior study of CGM in the perioperative period noted intermittent signal loss during operative time. Methods A prospective cohort analysis of 94 participants with hyperglycemia and/or diabetes mellitus undergoing surgery of 3 hours duration was conducted using Dexcom G6 and/or Freestyle Libre 2. 0 CGM. CGMs were placed preoperatively and compared to standard of care BG checks in the perioperative setting. Correction insulin was administered based on fingerstick glucoses. Of those consented, 18 were excluded resulting in 76 enrolled subjects. Results Preliminary data for use of CGM in perioperative period analyzed 50 participants with Freestyle Libre 2. 0 CGM, 20 participants with Dexcom G6 CGM, and 6 participants with both devices worn simultaneously. Lost sensor data occurred for 3 participants wearing Dexcom G6 CGM and 10 participants wearing Freestyle Libre 2. 0 CGM, which affected 2 of the participants wearing both devices simultaneously. The absolute difference of Dexcom G6 CGM glucose readings compared to BG readings was 29.17 mg/dL (SD = 22.15). The absolute difference of Freestyle Libre 2. 0 CGM glucose readings compared to BG readings was 26.94 mg/dL (SD = 24.16). There was not a significant difference in averages of absolute change in glucose when comparing Dexcom G6 CGM to Freestyle Libre 2. 0 CGM when utilized simultaneously. Grounding devices utilized Megadyne grounding pad for use of bipolar cautery, monopolar cautery, and surgeries with da Vinci robot. Of the 13 participants with lost data, 3 patients had bipolar cautery reported as being used at least once and 10 participants with lost data utilized monopolar cautery. None of the 6 participants with surgery utilizing da Vinci robot had loss of CGM data. Conclusion Both Dexcom G6 and Freestyle Libre 2. 0 CGMs were able to be utilized in the perioperative setting and generally functioned well. Use of CGM provided more glycemic data and better characterized glycemic trends than individual BG readings. It is anticipated that this technology could improve prevention of hypoglycemic events and better glycemic control in the perioperative setting. Use of CGMs in the perioperative setting is a novel area of application that warrants further evaluation of this technology. Presentation: No date and time listed