CONTEXT: The extent of the glycemic variability in diabetes secondary to total pancreatectomy is not fully understood. OBJECTIVE: To evaluate glycemic variability in totally pancreatectomized (PX) patients and compare it to glycemic variability in hemoglobin A1c (HbA1c)-matched patients with long-standing type 1 diabetes (T1D). DESIGN: A case-control study was performed. SETTING: Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark. PATIENTS OR OTHER PARTICIPANTS: Ten PX patients (mean [SEM]: age 64.3 [9.8] years; body mass index (BMI) 34.4 [5.0] kg/m2; duration of diabetes 3 [2.8] years), 10 HbA1c-matched patients with T1D (63.9 [8.6] years; 24.6 [3.1] kg/m2; 22 [4] years), and 10 gender-, age-, and BMI-matched healthy controls. All patients were managed on multiple daily injections of insulin. INTERVENTION: Continuous glucose monitoring (CGM) (Medtronic MiniMed iPro 2) during 12 consecutive days. MAIN OUTCOME MEASURES: Glycemic variability. RESULTS: HbA1c levels were similar in the PX group and the T1D group. The PX group had greater continuous overall net glycemic action per 60 minutes (CONGA60 min) compared with the T1D group (mean [SEM]: 9.5 [0.3] vs 8.3 [0.2] mmol/L, P < 0.003) and mean plasma glucose values were higher in the PX group (10.6 [0.9] vs 9.0 [0.9] mmol/L, P < 0.001), whereas coefficient of variation for plasma glucose and standard deviation of mean plasma glucose, respectively, were similar in the 2 groups. Time spent below range was not different between the PX and the T1D group (2.3 [0.8] vs 4.5 [0.8]%, P = 0.065), whereas time spent above range was higher in the PX group (51.4 [3.3] vs 37.6 [1.9]%, P < 0.001). CONCLUSIONS: CGM-assessed glycemic variability showed higher CONGA60 min and time spent above range in our PX patients compared with HbA1c-matched T1D patients. This study is registered at www.ClinicalTrials.gov (NCT02944110).