OBJECTIVES: Type 2 diabetes mellitus (T2DM) patients often have co-existing hypertension and dyslipidemia and some develop retinopathy, peripheral vascular disease (PVD), stroke, nephropathy and coronary heart disease (CAD). This study investigates the prevalence of these conditions which are associated with T2DM and the association with optimal glycaemic control(HbA1c up to 7%). METHODS: This is a cross-sectional study. We included all T2DM patients who were treated at the specialist outpatient clinics (SOCs) in 3 public-sector hospitals in Singapore during January 2009 and were on follow-up at the same clinic for at least 12 months. All data were extracted from the National Healthcare Group (NHG) Diabetes Registry (CDMS), including the medical diagnosis and HbA1c result at the last visit. We compared the distribution of glycaemic control for each diabetes-related condition and performed logistic regression for “optimal” glycaemic control adjusting for age, gender and ethnicity.RESULTS: Of the 3,420 T2DM patients, 2,919 (85%) with HbA1c results were analysed. Mean age was 63.2 years, with 53% female and 66% Chinese, high prevalence of dyslipidaemia (92.7%) and hypertension (74.5%). About 1,249 (42.8%) patients had “optimal” glycaemic control. CAD (28.7%) was the most common condition, followed by PVD (22.5%), retinopathy (21.8%), nephropathy (14.4%) and stroke (10.7%). The Malay group had the highest proportion of hypertension (78.8%), retinopathy (27.9%) and nephropathy (22.2%); Indian were highest in PVD (26.8%) and CAD (34.4%); Chinese highest in stroke (12.1%). After adjusting for age, gender and ethnicity, the odds of having “optimal” glycaemic control was higher for T2DM patients with nephropathy [AdjOR:1.50;95%CI(1.19-1.89)] and stroke [AdjOR:1.51;95%CI(1.17-1.96)] compared to PVD [AdjOR:0.61;95%CI(0.51-0.74)] and retinopathy [AdjOR:0.65;95%CI(0.53-0.79)]. CONCLUSIONS: There were ethnic differences in the prevalence of diabetes-related complications. T2DM patients with stroke or nephropathy were more likely to achieve “optimal” HbA1c level than those with PVD or eye complications. (294 words)