Objective: For appropriate care in diabetes regular monitor of blood glucose is needed. Self-monitoring of blood glucose (SMBG) has its own limitations; flash glucose monitoring (FGM) systems are now increasingly used for managing blood glucose. This rapid review to assessed evidence from randomized control trials (RCTs) on comparative efficacy of FGM vs. SMBG in patients with diabetes. Methods: In April 2019, we searched PubMed, Embase, and Cochrane for last five years. RCTs assessing efficacy of FGM vs. SMBG in diabetic patients published in English were included. Two reviewers screened titles, abstracts, and full-text independently and assessed studies for inclusion and quality. Data on study design, population characteristic, and clinical efficacy were extracted. Results: Of 332 articles screened, 3 articles reporting 2 RCTs consisting 465 patients conducted in Europe with 6-months follow-up were included. 269 and 196 patients received FGM and SMBG, respectively. A significant reduction of 38-46% and 43% for meantime (hours) spent in hypoglycemia, and 26-33% and 28% for mean hypoglycemic events was observed in type 1 (T1D) and type 2 diabetes (T2D) patients, respectively for FGM vs. SMBG. For time above target-glucose range, a significant reduction of 19% was observed for overall T1D patients; no significance was achieved in T2D population, for FGM vs. SMBG. In FGM group, significant reduction was observed in glucose variability for both T1D and T2D while time spent in target glucose range was significantly improved in T1D population only. Conclusion: FGM was effective in reducing mean hypoglycemic events and meantime spent in hypoglycemia for both T1D and T2D patients on intensive insulin therapy. In T1D, FGM was also effective in reducing glucose variability and time above target glucose range, and increased the time spent in target glucose range. However, lack of long term data from RCTs comparing FGM with SMBG calls for a RCTs with longer follow-up.