Background: The haemoglobin glycation index (HGI)has been proposed as a marker of interindividual differences in haemoglobin glycosylation. Previous studies have shown a relationship between high HGI and risk of cardiovascular disease (CVD)in patients with diabetes. However, no studies have investigated the role of previous CVD in this association. Methods: The study cohort comprised patients with type 2 diabetes mellitus (T2DM; n = 1910)included in the Second Manifestations of Arterial Disease (SMART)study. The relationship between either HGI or HbA_1c and a composite of cardiovascular events as the primary outcome, and mortality, cardiovascular mortality, myocardial infarction and stroke as secondary outcomes, was investigated using Cox proportional-hazards models. Similar analyses were performed after stratification according to previous CVD. Results: A 1-unit higher HGI was associated with a 29% greater risk of a composite of cardiovascular events (HR: 1.29, 95% CI: 1.06–1.57)in patients without previous CVD, whereas no such relationship was seen in patients with previous CVD (HR: 0.96, 95% CI: 0.86–1.08). The direction and magnitude of the hazard ratios (HRs)of HGI and HbA_1c in relation to outcomes were similar. Additional adjustment for HbA_1c in the association between HGI and outcomes lowered the HRs. Conclusion: Similar to HbA_1c, higher HGI is related to higher risk of cardiovascular events in patients with T2DM without CVD. As HbA_1c has proved to be a comparable risk factor, and obtaining and interpreting the HGI is complicated, any additional benefit of applying the HGI in clinical settings is likely to be limited.