A key aim of management in people with diabetes mellitus is to control blood glucose concentrations, in order to avoid the complications of persistently raised levels (with their attendant healthcare costs) and improve quality of life. However, such control is associated with an increased likelihood of hypoglycaemia, particularly among patients on insulin therapy. In pursuit of good glycaemic control while avoiding hypoglycaemia, self-monitoring of blood glucose is widely acknowledged as a routine part of management in patients with type 1 diabetes. However, the cost of monitoring products has now become a major issue for healthcare providers. This has led to some restrictions being placed on self-monitoring, especially for patients with type 2 diabetes, where the evidence for a benefit is less clear-cut. With this in mind, we review the data relating to the benefits of self-monitoring in adults with diabetes, particularly those with type 2 disease.