OBJECTIVE: To examine if clustering of cardiometabolic risk factors in pregnancy predicts type 2 diabetes and cardiovascular disease (CVD) risk at 10 years in women with gestational diabetes mellitus (GDM). STUDY DESIGN AND SUBJECTS: A prospective case-control study in 150 GDM and 72 overweight women with normal glucose tolerance (NGT) measured cardiometabolic risk factors (body mass index (BMI), systolic blood pressure (SBP), fasting glucose, insulin, and triglycerides and high-density lipoprotein (HDL) cholesterol) at 28 weeks gestation and 6 months and 10 years after pregnancy. Cluster analysis of cardiometabolic risk factors in pregnancy was used to stratify GDM as 'high' and 'low risk' for diabetes and CVD risk at 10 years. The data in pregnancy were used to determine a simple method for assessing risk of future diabetes. RESULTS: BMI in the 150 GDM at study entry was similar to NGT, but 35% of GDM fell into a 'high-risk cluster' with elevated BMI, SBP, glucose, insulin and triglycerides and lower HDL levels. At 10 years, type 2 diabetes was sixfold higher in 'high-risk' GDM (odds ratio (OR)=6.75, confidence interval (CI)=2.0, 22.7, P=0.002) compared with 'low-risk' GDM and was not reported in NGT. The 'high-risk' cluster predicted type 2 diabetes better than BMI430 (OR=2.13, CI=0.71, 6.4, P=0.179) or fasting glucose >5.5 mmol l-1, (OR=4.56, CI=1.50, 13.85, P=0.007). We determined that GDM with any four of the cardiometabolic risk factors (BMI430 kgm-2, fasting glucose>5.0 mmol l-1, insulin>7.8mUl-1, triglycerides >2.4 mmol l-1, HDL105mmHg) in pregnancy would be in a 'high-risk' cluster. CONCLUSIONS: A metabolic syndrome-like cluster in pregnant GDM identifies risk for type 2 diabetes providing an opportunity to focus on rigorous lifestyle interventions after delivery to reduce the burden of disease attributed to this condition. © 2013 Macmillan Publishers Limited All rights reserved.