AIMS: Systematic review and meta-analysis to evaluate the effect of Self-Monitoring of Blood Glucose (SMBG) on glycemic control in patients with type 2 Diabetes (T2D). METHODS: We searched the Medline, Embase, Cochrane Central, and ClinicalTrials.gov databases up to 20 July 2017. We also performed a manual search of abstracts from recent meetings of the American Diabetes Association and the European Association for the Study of Diabetes. STUDY SELECTION: randomized controlled trials (RCTs) conducted in patients with T2D comparing any kind of SMBG to a control group. Two independent reviewers assessed the eligibility of references. Influence of SMBG in glycated hemoglobin (HbA1c) was aggregated as weighted mean difference accessed by direct random effect meta-analyses at 12, 24 weeks and 1 year. Sub-analyses were made to assess the effects of previous glycemic control and number of tests performed. RESULTS: SMBG was associated with a reduction of HbA1c at 12 weeks (-0.31%; 95% CI: -0.57 to -0.05) and 24 weeks (-0.34%; 95%CI: -0.52 to -0.17), but no difference was found for 1 year. Subgroup analysis including studies with baseline HbA1c greater than 8% showed a higher reduction of HbA1c: -0.83% (95% CI: -1.55 to -0.11) at 12 weeks, and -0.48% (95% CI: -0.77 to -0.19) at 24 weeks, with no difference for 1 year nor for the stratification for number the tests. CONCLUSION: SMBG seems to lead to a slightly better glycemic control in the short term in patients with T2D. Patients decompensated at baseline appear to have the greatest benefit.