Diabetes mellitus, in particular Type 2 diabetes, can be classified as a chronic disease of lifestyle. A lifestyle intervention programme is therefore an essential component of the primary and secondary prevention (management) of diabetes mellitus. The main indication for referral to a lifestyle intervention programme is any patient with either pre-diabetes or established diabetes mellitus. Following a comprehensive initial assessment, patients are recommended to attend either a group-based programme (medically supervised or medically directed, depending on the severity of the disease and the presence of any co-morbidities) or a home-based intervention programme. The main elements of the intervention programme are nutritional intervention, exercise training (minimum of 150 minutes at moderate intensity per week), psychosocial support and education. Regular monitoring should be conducted during training sessions, and a follow-up assessment is indicated after 2–3 months to assess progress and to re-set goals. Longer-term (5–6 months) intervention programmes are associated with better long-term outcomes.