OBJECTIVES: Previous studies on the differences in the mechanism and complications of diabetes between men and women have indicated potential sex differences in cardiovascular health, which affect health-related quality of life (HRQoL). DESIGN: A cross-sectional cohort study. SETTING: To determine how sex differences can be noticed, acknowledged and applied in clinical practice, we aimed to determine the cardiovascular (CV) health status of men and women with diabetes and its effects on HRQoL. PARTICIPANTS: In total, 2829 individuals with diabetes (1518 men and 1311 women) aged ≥40 years who participated in the Korean National Health and Nutrition Examination Survey from 2013 to 2018 were enrolled. OUTCOME MEASURES: Individuals with diabetes were categorised into poor, intermediate and ideal groups based on CV health indicators recommended by the American Heart Association. We used EQ-5D-3L to compare HRQoL scores between the sexes. Multivariable ordinal logistic regression and analysis of covariance were used to analyse the outcome variables. RESULTS: In the poor CV health score group, female sex was associated with mobility problems (OR 1.93, 95% CI 1.46 to 2.54), problems with usual activities (OR1.71, 95% CI 1.24 to 2.35), pain/discomfort (OR 1.69, 95% CI 1.32 to 2.16) and anxiety/depression (OR 1.66 95% CI 1.16 to 2.38). In the intermediate and ideal CV health score groups, female sex was associated with pain/discomfort (OR 1.57, 95% CI 1.15 to 2.15). Men had higher EQ-5D index scores in the poor and intermediate CV health score groups than did women. CONCLUSIONS: Although women tended to have high health-related CV health scores, HRQoL was lower in women than in men, especially in the poor CV health score group and in the pain/discomfort domain.