Type 2 diabetes mellitus (T2DM) is associated with a two- to four-fold increased risk of developing cardiovascular disease (CVD) and microvascular complications, which may already be present before diagnosis. It is, therefore, important to detect people with an increased risk of T2DM at an early stage. In order to identify individuals with so-called ‘pre-diabetes’, comprising impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), current guidelines have developed definitions based on fasting plasma glucose, two-hour glucose concentrations and haemoglobin A1c. Subjects with pre-diabetes are at an increased risk of developing T2DM and CVD. This elevated risk seems similar according to the different criteria used to define pre-diabetes. The risk of progression to T2DM or CVD does, however, depend on other risk factors such as sex, body mass index and ethnicity. Based on the risk factors to develop T2DM, many risk assessment models have been developed to identify those at highest risk. These models perform well to identify those at risk and could be used to initiate preventive interventions. Many studies have shown that lifestyle modification and metformin are effective in preventing the development of T2DM, although lifestyle modification seems to have a more sustainable effect. In addition, lifestyle modification seems more effective in those with IGT than those with IFG. In this review, we will describe the different definitions used to define pre-diabetes, progression from pre-diabetes to T2DM or other vascular complications, risk factors associated with progressions and the management of progression to T2DM, ending with clinical recommendations.