OBJECTIVES: Glucose monitoring is particularly important for patients with diabetes treated with insulin.  Conventional self-monitoring of blood glucose (SMBG) requires a blood sample, typically obtained by pricking the finger with a lancing device.  A new device (FreeStyle Libre™ flash glucose monitoring system) has been developed to monitor glucose levels with a sensor worn on the arm, without requiring blood samples.  This study estimated utility associated with these two glucose monitoring approaches so that the values may be used in cost-utility models. METHODS: In time trade-off (TTO) interviews, general population participants in the UK (London, Edinburgh) valued two health states which were drafted based on literature and clinician interviews.  The health states had identical descriptions of diabetes and insulin treatment, but differed in glucose monitoring with either the FreeStyle Lite™ (SMBG) or the FreeStyle Libre (flash monitoring) system. RESULTS: A total of 209 participants completed interviews (51.7% female; mean age = 42.1 y).  Mean (SD) utilities were 0.851 (0.140) for SMBG and 0.882 (0.121) for flash monitoring (significant difference between the mean utilities; t = 8.3; p < 0.0001).  Of the 209 participants, 78 (37.3%) had a higher utility for flash monitoring, two (0.96%) had a higher utility for SMBG, and 129 (61.7%) had the same utility for both health states.  The mean score on a seven-point preference scale ranging from strongly prefer flash monitoring (1) to strongly prefer SMBG (7) indicates that the participants generally preferred the flash monitoring system (mean = 1.8; SD =1.5). CONCLUSIONS: The flash monitoring system was associated with significantly greater utility than SMBG.  This difference can be used in cost-utility models, comparing the value of glucose monitoring devices for patients with diabetes. This study also demonstrates that the TTO method may be used to quantify preferences for medical devices.