Summary: Advanced technologies associated with diabetes care, such as continuous glucose monitoring (CGM) and flash glucose monitoring (FGM) systems, have opened up new possibilities for diabetes management over the last two decades. Self-monitoring of blood glucose (SMBG) is a key component of successful diabetes management; however, it has relevant limitations (it requires a fingerstick to obtain a blood sample, it only provides a single “point-in-time” measurement). CGM, on the other hand, provides information about glucose concentrations as often as every few minutes, during all daily activities and during sleep, as well as trend information about the direction and rate of changing glucose concentrations. Numerous studies have shown that proper use of CGM/FGM is particularly useful in subgroups of patients with type 1 diabetes treated with either CSII or MDI therapy and in selected patients with type 2 diabetes, playing an important role in assessing the effectiveness and safety of therapy (better metabolic control, improved quality of life, reduced number of hypoglycemia episodes). CGM/FGM may also be helpful in participation in sports by patients with diabetes, to guide insulin therapy and increase its safety. CGM systems with alarms (alarms and alerts provided on receivers or on-body vibe alerts on transmitters) may be a particularly useful tool in patients with hypoglycemia unawareness or overnight hypoglycemia. Structured diabetes education and training is needed when prescribing CGM/FGM, with special attention to proper interpretation of glucose readings and BG trends for the current therapy. Therapeutic success also depends, among other things, on adherence to regular use of sensors.