OBJECTIVES: To describe the use of self-monitoring of blood glucose (SMBG) in a cohort of newly treated T2DM subjects and to assess the contribution of SMBG on overall antidiabetic and cardiovascular disease prescription costs. METHODS: A population based retrospective cohort study was conducted using the Irish national pharmacy claims database. Newly treated T2DM patients were identified for 2012 as being initiated on oral antidiabetic monotherapy and having received no antidiabetic therapy in the previous year. Subjects were followed for one year post treatment initiation. The association between prescription costs and SMBG  was assessed using generalised linear model with gamma family and log link functions to handle the right skew of the data adjusting for various demographic and treatment factors. Cost ratios and 95% CIs were obtained from this analysis and were used to determine the contribution of SMBG to prescription costs. RESULTS: A total of 12,941subjects were eligible for the study with 64% of subjects using SMBG. SMBG use was highest in subjects aged 40-49 years (71%) and decreased with age, with 48% of subjects aged 80-89 years using SMBG. Most subjects used SMBG greater than once a week but less than daily (41%) or daily and more frequently (51%). Use of SMBG resulted in dispensing costs that were overall 81% higher than those without SMBG use (95% CI 1.76, 1.92). CONCLUSIONS: Use of SMBG in newly treated T2DM was high including the frequency of use and resulted in high associated costs. SMBG represents a significant financial component in diabetes care, yet previous work has shown no clear benefit in newly treated type 2 diabetes patients on oral therapy. There is the potential for cost savings by introducing a review or limit on the amount of SMBG tests available to newly treated T2DM patients.