BACKGROUND: To assess the incidence of dysglycaemia and metabolic syndrome and factors associated with them 5 months postpartum in women with gestational diabetes mellitus (GDM) in their last pregnancy. METHODS: We conducted an observational prospective cohort study in 558 women with previous GDM who attended a 5-month postpartum follow-up clinic. Backward elimination was performed to select significant factors for the multivariable logistic regression model. Dysglycaemia (prediabetes and type 2 diabetes (T2D)) and metabolic syndrome were used as outcomes in separate models. RESULTS: Dysglycaemia was diagnosed in 202 (36.2%) women, including 174 (31.2%) with prediabetes and 28 (5.0%) with T2D. Women with dysglycaemia, compared with those with normoglycaemia, were more likely to be of black ethnicity (33.2 vs. 20.5%) and have severe GDM (31.7 vs. 16%), a higher postpartum BMI (29.5 vs. 27.6 kg/m CONCLUSIONS: At 5 months postpartum, a high proportion of women who developed GDM showed evidence of dysglycaemia. Future studies should investigate interventions that could reduce the risk of short- and long-term consequences of suboptimal cardiometabolic health in such women.