Self-monitoring of blood glucose (SMBG) has been available for patients with diabetes for more than 30 years. Today, SMBG is an important component in diabetes management, helping patients achieve and maintain normal blood glucose concentrations. Implementation of SMBG as an effective glycaemic control tool requires that instruments have acceptable analytical quality, that the patients are educated in using them, and that actions are taken upon the results. This paper gives an overview of SMBG, including the history, clinical utility, principles of measurement and several aspects of analytical quality of SMBG. The latter comprises a standardised evaluation of SMBG performance, quality specifications as well as different approaches to monitor the quality of SMBG performance.