PURPOSE: The purpose of this study was to describe occurrences of hypoglycemia in the diabetic population undergoing hyperbaric oxygen therapy (HBOT). We also examined 2 secondary aims: link industry standards for management of hypoglycemia in the general diabetic population to the HBOT environment; and integrate HBOT data into an electronic health record system, as patients transition across inpatient and outpatient services and settings. DESIGN: A retrospective, descriptive study. SUBJECTS AND SETTING: The study took place within a hyperbaric medicine department located in a 1393-bed acute care medical center, part of a large, multihospital system. The study sample comprised 100 diabetic patients who underwent HBOT between January 1 and May 31, 2015. Sixty-seven percent were male; the mean age of participants was 62 years (range 32-92 years). Admission status was nearly equal with 53% hospital inpatients and 47% ambulatory outpatients. Hospital protocol required all patients to have a minimal prehyperbaric blood glucose level (BGL) of 100 mg/dL. RESULTS: The incidence of hypoglycemia (defined as a BGL <100 mg/dL, 5.5 mmol/L) was 122 of 1175 treatments (10.4%). Additional analysis was based on records for 66 of the 122 incidences with evaluable data from electronic medical records. The mean BGL pre-HBOT was 177.86 mg/dL, 6.54 mmol/L (range 53-439 mg/dL, 2.94-24.36 mmol/L); the mean BGL after HBOT was 165.09 mg/dL, 9.16 mmol/L (range 56-414 mg/dL, 3.11-22.98 mmol/L). Analysis of these 66 occurrences revealed that 52 of 66 (79%) were managed with high-carbohydrate juices and snacks; 8 of 66 (12%) received oral glucagon; and 6 of 66 (9%) received glucagon and high-carbohydrate snack. We found that standard treatment protocols for hypoglycemia ranged from 70 to 100 mg/dL, 3.89 to 5.55 mmol/L, for the general population and 80 to 120 mg/dL, 4.44 to 6.66 mmol/L, for the general diabetic population. We also found that HBOT diabetic data were not fully integrated into the electronic health records across all settings. CONCLUSIONS: Hypoglycemia is prevalent during HBOT. We recommend a minimum pre-treatment serum glucose of 120 mg/dL, 6.7 mmol/L.